(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('@mapbox/unitbezier')) :
  typeof define === 'function' && define.amd ? define(['exports', '@mapbox/unitbezier'], factory) :
  (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.maplibreGlStyleSpecification = {}, global.UnitBezier));
})(this, (function (exports, UnitBezier) { 'use strict';

  var $version = 8;
  var $root = {
  	version: {
  		required: true,
  		type: "enum",
  		values: [
  			8
  		]
  	},
  	name: {
  		type: "string"
  	},
  	metadata: {
  		type: "*"
  	},
  	center: {
  		type: "array",
  		value: "number"
  	},
  	zoom: {
  		type: "number"
  	},
  	bearing: {
  		type: "number",
  		"default": 0,
  		period: 360,
  		units: "degrees"
  	},
  	pitch: {
  		type: "number",
  		"default": 0,
  		units: "degrees"
  	},
  	light: {
  		type: "light"
  	},
  	terrain: {
  		type: "terrain"
  	},
  	sources: {
  		required: true,
  		type: "sources"
  	},
  	sprite: {
  		type: "sprite"
  	},
  	glyphs: {
  		type: "string"
  	},
  	transition: {
  		type: "transition"
  	},
  	layers: {
  		required: true,
  		type: "array",
  		value: "layer"
  	}
  };
  var sources = {
  	"*": {
  		type: "source"
  	}
  };
  var source = [
  	"source_vector",
  	"source_raster",
  	"source_raster_dem",
  	"source_geojson",
  	"source_video",
  	"source_image"
  ];
  var source_vector = {
  	type: {
  		required: true,
  		type: "enum",
  		values: {
  			vector: {
  			}
  		}
  	},
  	url: {
  		type: "string"
  	},
  	tiles: {
  		type: "array",
  		value: "string"
  	},
  	bounds: {
  		type: "array",
  		value: "number",
  		length: 4,
  		"default": [
  			-180,
  			-85.051129,
  			180,
  			85.051129
  		]
  	},
  	scheme: {
  		type: "enum",
  		values: {
  			xyz: {
  			},
  			tms: {
  			}
  		},
  		"default": "xyz"
  	},
  	minzoom: {
  		type: "number",
  		"default": 0
  	},
  	maxzoom: {
  		type: "number",
  		"default": 22
  	},
  	attribution: {
  		type: "string"
  	},
  	promoteId: {
  		type: "promoteId"
  	},
  	volatile: {
  		type: "boolean",
  		"default": false
  	},
  	"*": {
  		type: "*"
  	}
  };
  var source_raster = {
  	type: {
  		required: true,
  		type: "enum",
  		values: {
  			raster: {
  			}
  		}
  	},
  	url: {
  		type: "string"
  	},
  	tiles: {
  		type: "array",
  		value: "string"
  	},
  	bounds: {
  		type: "array",
  		value: "number",
  		length: 4,
  		"default": [
  			-180,
  			-85.051129,
  			180,
  			85.051129
  		]
  	},
  	minzoom: {
  		type: "number",
  		"default": 0
  	},
  	maxzoom: {
  		type: "number",
  		"default": 22
  	},
  	tileSize: {
  		type: "number",
  		"default": 512,
  		units: "pixels"
  	},
  	scheme: {
  		type: "enum",
  		values: {
  			xyz: {
  			},
  			tms: {
  			}
  		},
  		"default": "xyz"
  	},
  	attribution: {
  		type: "string"
  	},
  	volatile: {
  		type: "boolean",
  		"default": false
  	},
  	"*": {
  		type: "*"
  	}
  };
  var source_raster_dem = {
  	type: {
  		required: true,
  		type: "enum",
  		values: {
  			"raster-dem": {
  			}
  		}
  	},
  	url: {
  		type: "string"
  	},
  	tiles: {
  		type: "array",
  		value: "string"
  	},
  	bounds: {
  		type: "array",
  		value: "number",
  		length: 4,
  		"default": [
  			-180,
  			-85.051129,
  			180,
  			85.051129
  		]
  	},
  	minzoom: {
  		type: "number",
  		"default": 0
  	},
  	maxzoom: {
  		type: "number",
  		"default": 22
  	},
  	tileSize: {
  		type: "number",
  		"default": 512,
  		units: "pixels"
  	},
  	attribution: {
  		type: "string"
  	},
  	encoding: {
  		type: "enum",
  		values: {
  			terrarium: {
  			},
  			mapbox: {
  			},
  			geos: {
  			}
  		},
  		"default": "geos"
  	},
  	volatile: {
  		type: "boolean",
  		"default": false
  	},
  	"*": {
  		type: "*"
  	}
  };
  var source_geojson = {
  	type: {
  		required: true,
  		type: "enum",
  		values: {
  			geojson: {
  			}
  		}
  	},
  	data: {
  		required: true,
  		type: "*"
  	},
  	maxzoom: {
  		type: "number",
  		"default": 18
  	},
  	attribution: {
  		type: "string"
  	},
  	buffer: {
  		type: "number",
  		"default": 128,
  		maximum: 512,
  		minimum: 0
  	},
  	filter: {
  		type: "*"
  	},
  	tolerance: {
  		type: "number",
  		"default": 0.375
  	},
  	cluster: {
  		type: "boolean",
  		"default": false
  	},
  	clusterRadius: {
  		type: "number",
  		"default": 50,
  		minimum: 0
  	},
  	clusterMaxZoom: {
  		type: "number"
  	},
  	clusterMinPoints: {
  		type: "number"
  	},
  	clusterProperties: {
  		type: "*"
  	},
  	lineMetrics: {
  		type: "boolean",
  		"default": false
  	},
  	generateId: {
  		type: "boolean",
  		"default": false
  	},
  	promoteId: {
  		type: "promoteId"
  	}
  };
  var source_video = {
  	type: {
  		required: true,
  		type: "enum",
  		values: {
  			video: {
  			}
  		}
  	},
  	urls: {
  		required: true,
  		type: "array",
  		value: "string"
  	},
  	coordinates: {
  		required: true,
  		type: "array",
  		length: 4,
  		value: {
  			type: "array",
  			length: 2,
  			value: "number"
  		}
  	}
  };
  var source_image = {
  	type: {
  		required: true,
  		type: "enum",
  		values: {
  			image: {
  			}
  		}
  	},
  	url: {
  		required: true,
  		type: "string"
  	},
  	coordinates: {
  		required: true,
  		type: "array",
  		length: 4,
  		value: {
  			type: "array",
  			length: 2,
  			value: "number"
  		}
  	}
  };
  var layer = {
  	id: {
  		type: "string",
  		required: true
  	},
  	type: {
  		type: "enum",
  		values: {
  			fill: {
  			},
  			line: {
  			},
  			symbol: {
  			},
  			circle: {
  			},
  			heatmap: {
  			},
  			"fill-extrusion": {
  			},
  			raster: {
  			},
  			hillshade: {
  			},
  			colorramp: {
  			},
  			background: {
  			}
  		},
  		required: true
  	},
  	metadata: {
  		type: "*"
  	},
  	source: {
  		type: "string"
  	},
  	"source-layer": {
  		type: "string"
  	},
  	minzoom: {
  		type: "number",
  		minimum: 0,
  		maximum: 24
  	},
  	maxzoom: {
  		type: "number",
  		minimum: 0,
  		maximum: 24
  	},
  	filter: {
  		type: "filter"
  	},
  	layout: {
  		type: "layout"
  	},
  	paint: {
  		type: "paint"
  	}
  };
  var layout = [
  	"layout_fill",
  	"layout_line",
  	"layout_circle",
  	"layout_heatmap",
  	"layout_fill-extrusion",
  	"layout_symbol",
  	"layout_raster",
  	"layout_hillshade",
  	"layout_colorramp",
  	"layout_background"
  ];
  var layout_background = {
  	visibility: {
  		type: "enum",
  		values: {
  			visible: {
  			},
  			none: {
  			}
  		},
  		"default": "visible",
  		"property-type": "constant"
  	}
  };
  var layout_fill = {
  	"fill-sort-key": {
  		type: "number",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	visibility: {
  		type: "enum",
  		values: {
  			visible: {
  			},
  			none: {
  			}
  		},
  		"default": "visible",
  		"property-type": "constant"
  	}
  };
  var layout_circle = {
  	"circle-sort-key": {
  		type: "number",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	visibility: {
  		type: "enum",
  		values: {
  			visible: {
  			},
  			none: {
  			}
  		},
  		"default": "visible",
  		"property-type": "constant"
  	}
  };
  var layout_heatmap = {
  	visibility: {
  		type: "enum",
  		values: {
  			visible: {
  			},
  			none: {
  			}
  		},
  		"default": "visible",
  		"property-type": "constant"
  	}
  };
  var layout_line = {
  	"line-cap": {
  		type: "enum",
  		values: {
  			butt: {
  			},
  			round: {
  			},
  			square: {
  			}
  		},
  		"default": "butt",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"line-join": {
  		type: "enum",
  		values: {
  			bevel: {
  			},
  			round: {
  			},
  			miter: {
  			}
  		},
  		"default": "miter",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"line-miter-limit": {
  		type: "number",
  		"default": 2,
  		requires: [
  			{
  				"line-join": "miter"
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"line-round-limit": {
  		type: "number",
  		"default": 1.05,
  		requires: [
  			{
  				"line-join": "round"
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"line-sort-key": {
  		type: "number",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	visibility: {
  		type: "enum",
  		values: {
  			visible: {
  			},
  			none: {
  			}
  		},
  		"default": "visible",
  		"property-type": "constant"
  	}
  };
  var layout_symbol = {
  	"symbol-placement": {
  		type: "enum",
  		values: {
  			point: {
  			},
  			line: {
  			},
  			"line-center": {
  			}
  		},
  		"default": "point",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"symbol-spacing": {
  		type: "number",
  		"default": 250,
  		minimum: 1,
  		units: "pixels",
  		requires: [
  			{
  				"symbol-placement": "line"
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"symbol-avoid-edges": {
  		type: "boolean",
  		"default": false,
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"symbol-sort-key": {
  		type: "number",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"symbol-z-order": {
  		type: "enum",
  		values: {
  			auto: {
  			},
  			"viewport-y": {
  			},
  			source: {
  			}
  		},
  		"default": "auto",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-allow-overlap": {
  		type: "boolean",
  		"default": false,
  		requires: [
  			"icon-image",
  			{
  				"!": "icon-overlap"
  			}
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-overlap": {
  		type: "enum",
  		values: {
  			never: {
  			},
  			always: {
  			},
  			cooperative: {
  			}
  		},
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-ignore-placement": {
  		type: "boolean",
  		"default": false,
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-optional": {
  		type: "boolean",
  		"default": false,
  		requires: [
  			"icon-image",
  			"text-field"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-rotation-alignment": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			},
  			auto: {
  			}
  		},
  		"default": "auto",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-size": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		units: "factor of the original icon size",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-text-fit": {
  		type: "enum",
  		values: {
  			none: {
  			},
  			width: {
  			},
  			height: {
  			},
  			both: {
  			}
  		},
  		"default": "none",
  		requires: [
  			"icon-image",
  			"text-field"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-text-fit-padding": {
  		type: "array",
  		value: "number",
  		length: 4,
  		"default": [
  			0,
  			0,
  			0,
  			0
  		],
  		units: "pixels",
  		requires: [
  			"icon-image",
  			"text-field",
  			{
  				"icon-text-fit": [
  					"both",
  					"width",
  					"height"
  				]
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-image": {
  		type: "resolvedImage",
  		tokens: true,
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-rotate": {
  		type: "number",
  		"default": 0,
  		period: 360,
  		units: "degrees",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-padding": {
  		type: "padding",
  		"default": [
  			2
  		],
  		units: "pixels",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-keep-upright": {
  		type: "boolean",
  		"default": false,
  		requires: [
  			"icon-image",
  			{
  				"icon-rotation-alignment": "map"
  			},
  			{
  				"symbol-placement": [
  					"line",
  					"line-center"
  				]
  			}
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-offset": {
  		type: "array",
  		value: "number",
  		length: 2,
  		"default": [
  			0,
  			0
  		],
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-anchor": {
  		type: "enum",
  		values: {
  			center: {
  			},
  			left: {
  			},
  			right: {
  			},
  			top: {
  			},
  			bottom: {
  			},
  			"top-left": {
  			},
  			"top-right": {
  			},
  			"bottom-left": {
  			},
  			"bottom-right": {
  			}
  		},
  		"default": "center",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-pitch-alignment": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			},
  			auto: {
  			}
  		},
  		"default": "auto",
  		requires: [
  			"icon-image"
  		],
  		expression: {
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  };
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  };
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  	"paint_heatmap",
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  	"paint_symbol",
  	"paint_raster",
  	"paint_hillshade",
  	"paint_colorramp",
  	"paint_background"
  ];
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  			{
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  				"feature"
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  		maximum: 1,
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  		transition: true,
  		requires: [
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  				"!": "line-pattern"
  			}
  		],
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  			{
  				"!": "line-pattern"
  			}
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "cross-faded"
  	},
  	"line-pattern": {
  		type: "resolvedImage",
  		transition: true,
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "cross-faded-data-driven"
  	},
  	"line-gradient": {
  		type: "color",
  		transition: false,
  		requires: [
  			{
  				"!": "line-dasharray"
  			},
  			{
  				"!": "line-pattern"
  			},
  			{
  				source: "geojson",
  				has: {
  					lineMetrics: true
  				}
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"line-progress"
  			]
  		},
  		"property-type": "color-ramp"
  	}
  };
  var paint_circle = {
  	"circle-radius": {
  		type: "number",
  		"default": 5,
  		minimum: 0,
  		transition: true,
  		units: "pixels",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"circle-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"circle-blur": {
  		type: "number",
  		"default": 0,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"circle-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"circle-translate": {
  		type: "array",
  		value: "number",
  		length: 2,
  		"default": [
  			0,
  			0
  		],
  		transition: true,
  		units: "pixels",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"circle-translate-anchor": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "map",
  		requires: [
  			"circle-translate"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"circle-pitch-scale": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "map",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"circle-pitch-alignment": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "viewport",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"circle-stroke-width": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		transition: true,
  		units: "pixels",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"circle-stroke-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"circle-stroke-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	}
  };
  var paint_heatmap = {
  	"heatmap-radius": {
  		type: "number",
  		"default": 30,
  		minimum: 1,
  		transition: true,
  		units: "pixels",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"heatmap-weight": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		transition: false,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"heatmap-intensity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"heatmap-color": {
  		type: "color",
  		"default": [
  			"interpolate",
  			[
  				"linear"
  			],
  			[
  				"heatmap-density"
  			],
  			0,
  			"rgba(0, 0, 255, 0)",
  			0.1,
  			"royalblue",
  			0.3,
  			"cyan",
  			0.5,
  			"lime",
  			0.7,
  			"yellow",
  			1,
  			"red"
  		],
  		transition: false,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"heatmap-density"
  			]
  		},
  		"property-type": "color-ramp"
  	},
  	"heatmap-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  };
  var paint_symbol = {
  	"icon-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-halo-color": {
  		type: "color",
  		"default": "rgba(0, 0, 0, 0)",
  		transition: true,
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-halo-width": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		transition: true,
  		units: "pixels",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-halo-blur": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		transition: true,
  		units: "pixels",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"icon-translate": {
  		type: "array",
  		value: "number",
  		length: 2,
  		"default": [
  			0,
  			0
  		],
  		transition: true,
  		units: "pixels",
  		requires: [
  			"icon-image"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"icon-translate-anchor": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "map",
  		requires: [
  			"icon-image",
  			"icon-translate"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"text-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		requires: [
  			"text-field"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"text-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		overridable: true,
  		requires: [
  			"text-field"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"text-halo-color": {
  		type: "color",
  		"default": "rgba(0, 0, 0, 0)",
  		transition: true,
  		requires: [
  			"text-field"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"text-halo-width": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		transition: true,
  		units: "pixels",
  		requires: [
  			"text-field"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"text-halo-blur": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		transition: true,
  		units: "pixels",
  		requires: [
  			"text-field"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"text-translate": {
  		type: "array",
  		value: "number",
  		length: 2,
  		"default": [
  			0,
  			0
  		],
  		transition: true,
  		units: "pixels",
  		requires: [
  			"text-field"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"text-translate-anchor": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "map",
  		requires: [
  			"text-field",
  			"text-translate"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  };
  var paint_raster = {
  	"raster-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-hue-rotate": {
  		type: "number",
  		"default": 0,
  		period: 360,
  		transition: true,
  		units: "degrees",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-brightness-min": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-brightness-max": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-saturation": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-contrast": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-resampling": {
  		type: "enum",
  		values: {
  			linear: {
  			},
  			nearest: {
  			}
  		},
  		"default": "linear",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"raster-fade-duration": {
  		type: "number",
  		"default": 300,
  		minimum: 0,
  		transition: false,
  		units: "milliseconds",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  };
  var paint_hillshade = {
  	"hillshade-illumination-direction": {
  		type: "number",
  		"default": 335,
  		minimum: 0,
  		maximum: 359,
  		transition: false,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-illumination-anchor": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "viewport",
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-exaggeration": {
  		type: "number",
  		"default": 0.5,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-shadow-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-highlight-color": {
  		type: "color",
  		"default": "#FFFFFF",
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-accent-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"global-ramp": {
  		type: "array",
  		value: "number",
  		"property-type": "data-constant"
  	},
  	"hillshade-test": {
  		type: "number",
  		"default": 0.5,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"layers-opacityHillshade": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"layers-opacitySlope": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"layers-opacityColors": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"global-brightness": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"global-contrast": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"global-exposure": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-brightness": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-contrast": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-exposure": {
  		type: "number",
  		"default": 0,
  		minimum: -1,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-zfactor": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 100,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-azimuth": {
  		type: "number",
  		"default": 315,
  		minimum: 0,
  		maximum: 360,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"hillshade-zenith": {
  		type: "number",
  		"default": 45,
  		minimum: 0,
  		maximum: 90,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  };
  var paint_colorramp = {
  	ramp: {
  		type: "array",
  		value: "number",
  		"property-type": "data-constant"
  	},
  	"colorramp-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  };
  var paint_background = {
  	"background-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		requires: [
  			{
  				"!": "background-pattern"
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"background-pattern": {
  		type: "resolvedImage",
  		transition: true,
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "cross-faded"
  	},
  	"background-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  };
  var transition = {
  	duration: {
  		type: "number",
  		"default": 300,
  		minimum: 0,
  		units: "milliseconds"
  	},
  	delay: {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		units: "milliseconds"
  	}
  };
  var promoteId = {
  	"*": {
  		type: "string"
  	}
  };
  var v8Spec = {
  	$version: $version,
  	$root: $root,
  	sources: sources,
  	source: source,
  	source_vector: source_vector,
  	source_raster: source_raster,
  	source_raster_dem: source_raster_dem,
  	source_geojson: source_geojson,
  	source_video: source_video,
  	source_image: source_image,
  	layer: layer,
  	layout: layout,
  	layout_background: layout_background,
  	layout_fill: layout_fill,
  	layout_circle: layout_circle,
  	layout_heatmap: layout_heatmap,
  	"layout_fill-extrusion": {
  	visibility: {
  		type: "enum",
  		values: {
  			visible: {
  			},
  			none: {
  			}
  		},
  		"default": "visible",
  		"property-type": "constant"
  	}
  },
  	layout_line: layout_line,
  	layout_symbol: layout_symbol,
  	layout_raster: layout_raster,
  	layout_hillshade: layout_hillshade,
  	layout_colorramp: layout_colorramp,
  	filter: filter,
  	filter_operator: filter_operator,
  	geometry_type: geometry_type,
  	"function": {
  	expression: {
  		type: "expression"
  	},
  	stops: {
  		type: "array",
  		value: "function_stop"
  	},
  	base: {
  		type: "number",
  		"default": 1,
  		minimum: 0
  	},
  	property: {
  		type: "string",
  		"default": "$zoom"
  	},
  	type: {
  		type: "enum",
  		values: {
  			identity: {
  			},
  			exponential: {
  			},
  			interval: {
  			},
  			categorical: {
  			}
  		},
  		"default": "exponential"
  	},
  	colorSpace: {
  		type: "enum",
  		values: {
  			rgb: {
  			},
  			lab: {
  			},
  			hcl: {
  			}
  		},
  		"default": "rgb"
  	},
  	"default": {
  		type: "*",
  		required: false
  	}
  },
  	function_stop: function_stop,
  	expression: expression$1,
  	light: light,
  	terrain: terrain,
  	paint: paint,
  	paint_fill: paint_fill,
  	"paint_fill-extrusion": {
  	"fill-extrusion-opacity": {
  		type: "number",
  		"default": 1,
  		minimum: 0,
  		maximum: 1,
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"fill-extrusion-color": {
  		type: "color",
  		"default": "#000000",
  		transition: true,
  		requires: [
  			{
  				"!": "fill-extrusion-pattern"
  			}
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"fill-extrusion-translate": {
  		type: "array",
  		value: "number",
  		length: 2,
  		"default": [
  			0,
  			0
  		],
  		transition: true,
  		units: "pixels",
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"fill-extrusion-translate-anchor": {
  		type: "enum",
  		values: {
  			map: {
  			},
  			viewport: {
  			}
  		},
  		"default": "map",
  		requires: [
  			"fill-extrusion-translate"
  		],
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	},
  	"fill-extrusion-pattern": {
  		type: "resolvedImage",
  		transition: true,
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom",
  				"feature"
  			]
  		},
  		"property-type": "cross-faded-data-driven"
  	},
  	"fill-extrusion-height": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		units: "meters",
  		transition: true,
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"fill-extrusion-base": {
  		type: "number",
  		"default": 0,
  		minimum: 0,
  		units: "meters",
  		transition: true,
  		requires: [
  			"fill-extrusion-height"
  		],
  		expression: {
  			interpolated: true,
  			parameters: [
  				"zoom",
  				"feature",
  				"feature-state"
  			]
  		},
  		"property-type": "data-driven"
  	},
  	"fill-extrusion-vertical-gradient": {
  		type: "boolean",
  		"default": true,
  		transition: false,
  		expression: {
  			interpolated: false,
  			parameters: [
  				"zoom"
  			]
  		},
  		"property-type": "data-constant"
  	}
  },
  	paint_line: paint_line,
  	paint_circle: paint_circle,
  	paint_heatmap: paint_heatmap,
  	paint_symbol: paint_symbol,
  	paint_raster: paint_raster,
  	paint_hillshade: paint_hillshade,
  	paint_colorramp: paint_colorramp,
  	paint_background: paint_background,
  	transition: transition,
  	"property-type": {
  	"data-driven": {
  		type: "property-type"
  	},
  	"cross-faded": {
  		type: "property-type"
  	},
  	"cross-faded-data-driven": {
  		type: "property-type"
  	},
  	"color-ramp": {
  		type: "property-type"
  	},
  	"data-constant": {
  		type: "property-type"
  	},
  	constant: {
  		type: "property-type"
  	}
  },
  	promoteId: promoteId
  };

  const refProperties = ['type', 'source', 'source-layer', 'minzoom', 'maxzoom', 'filter', 'layout'];

  function deref(layer, parent) {
      const result = {};
      for (const k in layer) {
          if (k !== 'ref') {
              result[k] = layer[k];
          }
      }
      refProperties.forEach((k) => {
          if (k in parent) {
              result[k] = parent[k];
          }
      });
      return result;
  }
  /**
   * Given an array of layers, some of which may contain `ref` properties
   * whose value is the `id` of another property, return a new array where
   * such layers have been augmented with the 'type', 'source', etc. properties
   * from the parent layer, and the `ref` property has been removed.
   *
   * The input is not modified. The output may contain references to portions
   * of the input.
   *
   * @private
   * @param {Array<Layer>} layers
   * @returns {Array<Layer>}
   */
  function derefLayers(layers) {
      layers = layers.slice();
      const map = Object.create(null);
      for (let i = 0; i < layers.length; i++) {
          map[layers[i].id] = layers[i];
      }
      for (let i = 0; i < layers.length; i++) {
          if ('ref' in layers[i]) {
              layers[i] = deref(layers[i], map[layers[i].ref]);
          }
      }
      return layers;
  }

  /**
   * Deeply compares two object literals.
   *
   * @private
   */
  function deepEqual(a, b) {
      if (Array.isArray(a)) {
          if (!Array.isArray(b) || a.length !== b.length)
              return false;
          for (let i = 0; i < a.length; i++) {
              if (!deepEqual(a[i], b[i]))
                  return false;
          }
          return true;
      }
      if (typeof a === 'object' && a !== null && b !== null) {
          if (!(typeof b === 'object'))
              return false;
          const keys = Object.keys(a);
          if (keys.length !== Object.keys(b).length)
              return false;
          for (const key in a) {
              if (!deepEqual(a[key], b[key]))
                  return false;
          }
          return true;
      }
      return a === b;
  }

  const operations = {
      /*
       * { command: 'setStyle', args: [stylesheet] }
       */
      setStyle: 'setStyle',
      /*
       * { command: 'addLayer', args: [layer, 'beforeLayerId'] }
       */
      addLayer: 'addLayer',
      /*
       * { command: 'removeLayer', args: ['layerId'] }
       */
      removeLayer: 'removeLayer',
      /*
       * { command: 'setPaintProperty', args: ['layerId', 'prop', value] }
       */
      setPaintProperty: 'setPaintProperty',
      /*
       * { command: 'setLayoutProperty', args: ['layerId', 'prop', value] }
       */
      setLayoutProperty: 'setLayoutProperty',
      /*
       * { command: 'setFilter', args: ['layerId', filter] }
       */
      setFilter: 'setFilter',
      /*
       * { command: 'addSource', args: ['sourceId', source] }
       */
      addSource: 'addSource',
      /*
       * { command: 'removeSource', args: ['sourceId'] }
       */
      removeSource: 'removeSource',
      /*
       * { command: 'setGeoJSONSourceData', args: ['sourceId', data] }
       */
      setGeoJSONSourceData: 'setGeoJSONSourceData',
      /*
       * { command: 'setLayerZoomRange', args: ['layerId', 0, 22] }
       */
      setLayerZoomRange: 'setLayerZoomRange',
      /*
       * { command: 'setLayerProperty', args: ['layerId', 'prop', value] }
       */
      setLayerProperty: 'setLayerProperty',
      /*
       * { command: 'setCenter', args: [[lon, lat]] }
       */
      setCenter: 'setCenter',
      /*
       * { command: 'setZoom', args: [zoom] }
       */
      setZoom: 'setZoom',
      /*
       * { command: 'setBearing', args: [bearing] }
       */
      setBearing: 'setBearing',
      /*
       * { command: 'setPitch', args: [pitch] }
       */
      setPitch: 'setPitch',
      /*
       * { command: 'setSprite', args: ['spriteUrl'] }
       */
      setSprite: 'setSprite',
      /*
       * { command: 'setGlyphs', args: ['glyphsUrl'] }
       */
      setGlyphs: 'setGlyphs',
      /*
       * { command: 'setTransition', args: [transition] }
       */
      setTransition: 'setTransition',
      /*
       * { command: 'setLighting', args: [lightProperties] }
       */
      setLight: 'setLight'
  };
  function addSource(sourceId, after, commands) {
      commands.push({ command: operations.addSource, args: [sourceId, after[sourceId]] });
  }
  function removeSource(sourceId, commands, sourcesRemoved) {
      commands.push({ command: operations.removeSource, args: [sourceId] });
      sourcesRemoved[sourceId] = true;
  }
  function updateSource(sourceId, after, commands, sourcesRemoved) {
      removeSource(sourceId, commands, sourcesRemoved);
      addSource(sourceId, after, commands);
  }
  function canUpdateGeoJSON(before, after, sourceId) {
      let prop;
      for (prop in before[sourceId]) {
          if (!Object.prototype.hasOwnProperty.call(before[sourceId], prop))
              continue;
          if (prop !== 'data' && !deepEqual(before[sourceId][prop], after[sourceId][prop])) {
              return false;
          }
      }
      for (prop in after[sourceId]) {
          if (!Object.prototype.hasOwnProperty.call(after[sourceId], prop))
              continue;
          if (prop !== 'data' && !deepEqual(before[sourceId][prop], after[sourceId][prop])) {
              return false;
          }
      }
      return true;
  }
  function diffSources(before, after, commands, sourcesRemoved) {
      before = before || {};
      after = after || {};
      let sourceId;
      // look for sources to remove
      for (sourceId in before) {
          if (!Object.prototype.hasOwnProperty.call(before, sourceId))
              continue;
          if (!Object.prototype.hasOwnProperty.call(after, sourceId)) {
              removeSource(sourceId, commands, sourcesRemoved);
          }
      }
      // look for sources to add/update
      for (sourceId in after) {
          if (!Object.prototype.hasOwnProperty.call(after, sourceId))
              continue;
          if (!Object.prototype.hasOwnProperty.call(before, sourceId)) {
              addSource(sourceId, after, commands);
          }
          else if (!deepEqual(before[sourceId], after[sourceId])) {
              if (before[sourceId].type === 'geojson' && after[sourceId].type === 'geojson' && canUpdateGeoJSON(before, after, sourceId)) {
                  commands.push({ command: operations.setGeoJSONSourceData, args: [sourceId, after[sourceId].data] });
              }
              else {
                  // no update command, must remove then add
                  updateSource(sourceId, after, commands, sourcesRemoved);
              }
          }
      }
  }
  function diffLayerPropertyChanges(before, after, commands, layerId, klass, command) {
      before = before || {};
      after = after || {};
      let prop;
      for (prop in before) {
          if (!Object.prototype.hasOwnProperty.call(before, prop))
              continue;
          if (!deepEqual(before[prop], after[prop])) {
              commands.push({ command, args: [layerId, prop, after[prop], klass] });
          }
      }
      for (prop in after) {
          if (!Object.prototype.hasOwnProperty.call(after, prop) || Object.prototype.hasOwnProperty.call(before, prop))
              continue;
          if (!deepEqual(before[prop], after[prop])) {
              commands.push({ command, args: [layerId, prop, after[prop], klass] });
          }
      }
  }
  function pluckId(layer) {
      return layer.id;
  }
  function indexById(group, layer) {
      group[layer.id] = layer;
      return group;
  }
  function diffLayers(before, after, commands) {
      before = before || [];
      after = after || [];
      // order of layers by id
      const beforeOrder = before.map(pluckId);
      const afterOrder = after.map(pluckId);
      // index of layer by id
      const beforeIndex = before.reduce(indexById, {});
      const afterIndex = after.reduce(indexById, {});
      // track order of layers as if they have been mutated
      const tracker = beforeOrder.slice();
      // layers that have been added do not need to be diffed
      const clean = Object.create(null);
      let i, d, layerId, beforeLayer, afterLayer, insertBeforeLayerId, prop;
      // remove layers
      for (i = 0, d = 0; i < beforeOrder.length; i++) {
          layerId = beforeOrder[i];
          if (!Object.prototype.hasOwnProperty.call(afterIndex, layerId)) {
              commands.push({ command: operations.removeLayer, args: [layerId] });
              tracker.splice(tracker.indexOf(layerId, d), 1);
          }
          else {
              // limit where in tracker we need to look for a match
              d++;
          }
      }
      // add/reorder layers
      for (i = 0, d = 0; i < afterOrder.length; i++) {
          // work backwards as insert is before an existing layer
          layerId = afterOrder[afterOrder.length - 1 - i];
          if (tracker[tracker.length - 1 - i] === layerId)
              continue;
          if (Object.prototype.hasOwnProperty.call(beforeIndex, layerId)) {
              // remove the layer before we insert at the correct position
              commands.push({ command: operations.removeLayer, args: [layerId] });
              tracker.splice(tracker.lastIndexOf(layerId, tracker.length - d), 1);
          }
          else {
              // limit where in tracker we need to look for a match
              d++;
          }
          // add layer at correct position
          insertBeforeLayerId = tracker[tracker.length - i];
          commands.push({ command: operations.addLayer, args: [afterIndex[layerId], insertBeforeLayerId] });
          tracker.splice(tracker.length - i, 0, layerId);
          clean[layerId] = true;
      }
      // update layers
      for (i = 0; i < afterOrder.length; i++) {
          layerId = afterOrder[i];
          beforeLayer = beforeIndex[layerId];
          afterLayer = afterIndex[layerId];
          // no need to update if previously added (new or moved)
          if (clean[layerId] || deepEqual(beforeLayer, afterLayer))
              continue;
          // If source, source-layer, or type have changes, then remove the layer
          // and add it back 'from scratch'.
          if (!deepEqual(beforeLayer.source, afterLayer.source) || !deepEqual(beforeLayer['source-layer'], afterLayer['source-layer']) || !deepEqual(beforeLayer.type, afterLayer.type)) {
              commands.push({ command: operations.removeLayer, args: [layerId] });
              // we add the layer back at the same position it was already in, so
              // there's no need to update the `tracker`
              insertBeforeLayerId = tracker[tracker.lastIndexOf(layerId) + 1];
              commands.push({ command: operations.addLayer, args: [afterLayer, insertBeforeLayerId] });
              continue;
          }
          // layout, paint, filter, minzoom, maxzoom
          diffLayerPropertyChanges(beforeLayer.layout, afterLayer.layout, commands, layerId, null, operations.setLayoutProperty);
          diffLayerPropertyChanges(beforeLayer.paint, afterLayer.paint, commands, layerId, null, operations.setPaintProperty);
          if (!deepEqual(beforeLayer.filter, afterLayer.filter)) {
              commands.push({ command: operations.setFilter, args: [layerId, afterLayer.filter] });
          }
          if (!deepEqual(beforeLayer.minzoom, afterLayer.minzoom) || !deepEqual(beforeLayer.maxzoom, afterLayer.maxzoom)) {
              commands.push({ command: operations.setLayerZoomRange, args: [layerId, afterLayer.minzoom, afterLayer.maxzoom] });
          }
          // handle all other layer props, including paint.*
          for (prop in beforeLayer) {
              if (!Object.prototype.hasOwnProperty.call(beforeLayer, prop))
                  continue;
              if (prop === 'layout' || prop === 'paint' || prop === 'filter' ||
                  prop === 'metadata' || prop === 'minzoom' || prop === 'maxzoom')
                  continue;
              if (prop.indexOf('paint.') === 0) {
                  diffLayerPropertyChanges(beforeLayer[prop], afterLayer[prop], commands, layerId, prop.slice(6), operations.setPaintProperty);
              }
              else if (!deepEqual(beforeLayer[prop], afterLayer[prop])) {
                  commands.push({ command: operations.setLayerProperty, args: [layerId, prop, afterLayer[prop]] });
              }
          }
          for (prop in afterLayer) {
              if (!Object.prototype.hasOwnProperty.call(afterLayer, prop) || Object.prototype.hasOwnProperty.call(beforeLayer, prop))
                  continue;
              if (prop === 'layout' || prop === 'paint' || prop === 'filter' ||
                  prop === 'metadata' || prop === 'minzoom' || prop === 'maxzoom')
                  continue;
              if (prop.indexOf('paint.') === 0) {
                  diffLayerPropertyChanges(beforeLayer[prop], afterLayer[prop], commands, layerId, prop.slice(6), operations.setPaintProperty);
              }
              else if (!deepEqual(beforeLayer[prop], afterLayer[prop])) {
                  commands.push({ command: operations.setLayerProperty, args: [layerId, prop, afterLayer[prop]] });
              }
          }
      }
  }
  /**
   * Diff two stylesheet
   *
   * Creates semanticly aware diffs that can easily be applied at runtime.
   * Operations produced by the diff closely resemble the maplibre-gl-js API. Any
   * error creating the diff will fall back to the 'setStyle' operation.
   *
   * Example diff:
   * [
   *     { command: 'setConstant', args: ['@water', '#0000FF'] },
   *     { command: 'setPaintProperty', args: ['background', 'background-color', 'black'] }
   * ]
   *
   * @private
   * @param {*} [before] stylesheet to compare from
   * @param {*} after stylesheet to compare to
   * @returns Array list of changes
   */
  function diffStyles(before, after) {
      if (!before)
          return [{ command: operations.setStyle, args: [after] }];
      let commands = [];
      try {
          // Handle changes to top-level properties
          if (!deepEqual(before.version, after.version)) {
              return [{ command: operations.setStyle, args: [after] }];
          }
          if (!deepEqual(before.center, after.center)) {
              commands.push({ command: operations.setCenter, args: [after.center] });
          }
          if (!deepEqual(before.zoom, after.zoom)) {
              commands.push({ command: operations.setZoom, args: [after.zoom] });
          }
          if (!deepEqual(before.bearing, after.bearing)) {
              commands.push({ command: operations.setBearing, args: [after.bearing] });
          }
          if (!deepEqual(before.pitch, after.pitch)) {
              commands.push({ command: operations.setPitch, args: [after.pitch] });
          }
          if (!deepEqual(before.sprite, after.sprite)) {
              commands.push({ command: operations.setSprite, args: [after.sprite] });
          }
          if (!deepEqual(before.glyphs, after.glyphs)) {
              commands.push({ command: operations.setGlyphs, args: [after.glyphs] });
          }
          if (!deepEqual(before.transition, after.transition)) {
              commands.push({ command: operations.setTransition, args: [after.transition] });
          }
          if (!deepEqual(before.light, after.light)) {
              commands.push({ command: operations.setLight, args: [after.light] });
          }
          // Handle changes to `sources`
          // If a source is to be removed, we also--before the removeSource
          // command--need to remove all the style layers that depend on it.
          const sourcesRemoved = {};
          // First collect the {add,remove}Source commands
          const removeOrAddSourceCommands = [];
          diffSources(before.sources, after.sources, removeOrAddSourceCommands, sourcesRemoved);
          // Push a removeLayer command for each style layer that depends on a
          // source that's being removed.
          // Also, exclude any such layers them from the input to `diffLayers`
          // below, so that diffLayers produces the appropriate `addLayers`
          // command
          const beforeLayers = [];
          if (before.layers) {
              before.layers.forEach((layer) => {
                  if (sourcesRemoved[layer.source]) {
                      commands.push({ command: operations.removeLayer, args: [layer.id] });
                  }
                  else {
                      beforeLayers.push(layer);
                  }
              });
          }
          commands = commands.concat(removeOrAddSourceCommands);
          // Handle changes to `layers`
          diffLayers(beforeLayers, after.layers, commands);
      }
      catch (e) {
          // fall back to setStyle
          console.warn('Unable to compute style diff:', e);
          commands = [{ command: operations.setStyle, args: [after] }];
      }
      return commands;
  }

  // Note: Do not inherit from Error. It breaks when transpiling to ES5.
  class ValidationError {
      constructor(key, value, message, identifier) {
          this.message = (key ? `${key}: ` : '') + message;
          if (identifier)
              this.identifier = identifier;
          if (value !== null && value !== undefined && value.__line__) {
              this.line = value.__line__;
          }
      }
  }

  // Note: Do not inherit from Error. It breaks when transpiling to ES5.
  class ParsingError {
      constructor(error) {
          this.error = error;
          this.message = error.message;
          const match = error.message.match(/line (\d+)/);
          this.line = match ? parseInt(match[1], 10) : 0;
      }
  }

  function extendBy(output, ...inputs) {
      for (const input of inputs) {
          for (const k in input) {
              output[k] = input[k];
          }
      }
      return output;
  }

  class ExpressionParsingError extends Error {
      constructor(key, message) {
          super(message);
          this.message = message;
          this.key = key;
      }
  }

  /**
   * Tracks `let` bindings during expression parsing.
   * @private
   */
  class Scope {
      constructor(parent, bindings = []) {
          this.parent = parent;
          this.bindings = {};
          for (const [name, expression] of bindings) {
              this.bindings[name] = expression;
          }
      }
      concat(bindings) {
          return new Scope(this, bindings);
      }
      get(name) {
          if (this.bindings[name]) {
              return this.bindings[name];
          }
          if (this.parent) {
              return this.parent.get(name);
          }
          throw new Error(`${name} not found in scope.`);
      }
      has(name) {
          if (this.bindings[name])
              return true;
          return this.parent ? this.parent.has(name) : false;
      }
  }

  const NullType = { kind: 'null' };
  const NumberType = { kind: 'number' };
  const StringType = { kind: 'string' };
  const BooleanType = { kind: 'boolean' };
  const ColorType = { kind: 'color' };
  const ObjectType = { kind: 'object' };
  const ValueType = { kind: 'value' };
  const ErrorType = { kind: 'error' };
  const CollatorType = { kind: 'collator' };
  const FormattedType = { kind: 'formatted' };
  const PaddingType = { kind: 'padding' };
  const ResolvedImageType = { kind: 'resolvedImage' };
  const VariableAnchorOffsetCollectionType = { kind: 'variableAnchorOffsetCollection' };
  function array$1(itemType, N) {
      return {
          kind: 'array',
          itemType,
          N
      };
  }
  function toString$1(type) {
      if (type.kind === 'array') {
          const itemType = toString$1(type.itemType);
          return typeof type.N === 'number' ?
              `array<${itemType}, ${type.N}>` :
              type.itemType.kind === 'value' ? 'array' : `array<${itemType}>`;
      }
      else {
          return type.kind;
      }
  }
  const valueMemberTypes = [
      NullType,
      NumberType,
      StringType,
      BooleanType,
      ColorType,
      FormattedType,
      ObjectType,
      array$1(ValueType),
      PaddingType,
      ResolvedImageType,
      VariableAnchorOffsetCollectionType
  ];
  /**
   * Returns null if `t` is a subtype of `expected`; otherwise returns an
   * error message.
   * @private
   */
  function checkSubtype(expected, t) {
      if (t.kind === 'error') {
          // Error is a subtype of every type
          return null;
      }
      else if (expected.kind === 'array') {
          if (t.kind === 'array' &&
              ((t.N === 0 && t.itemType.kind === 'value') || !checkSubtype(expected.itemType, t.itemType)) &&
              (typeof expected.N !== 'number' || expected.N === t.N)) {
              return null;
          }
      }
      else if (expected.kind === t.kind) {
          return null;
      }
      else if (expected.kind === 'value') {
          for (const memberType of valueMemberTypes) {
              if (!checkSubtype(memberType, t)) {
                  return null;
              }
          }
      }
      return `Expected ${toString$1(expected)} but found ${toString$1(t)} instead.`;
  }
  function isValidType(provided, allowedTypes) {
      return allowedTypes.some(t => t.kind === provided.kind);
  }
  function isValidNativeType(provided, allowedTypes) {
      return allowedTypes.some(t => {
          if (t === 'null') {
              return provided === null;
          }
          else if (t === 'array') {
              return Array.isArray(provided);
          }
          else if (t === 'object') {
              return provided && !Array.isArray(provided) && typeof provided === 'object';
          }
          else {
              return t === typeof provided;
          }
      });
  }
  /**
   * Verify whether the specified type is of the same type as the specified sample.
   *
   * @param provided Type to verify
   * @param sample Sample type to reference
   * @returns `true` if both objects are of the same type, `false` otherwise
   * @example basic types
   * if (verifyType(outputType, ValueType)) {
   *     // type narrowed to:
   *     outputType.kind; // 'value'
   * }
   * @example array types
   * if (verifyType(outputType, array(NumberType))) {
   *     // type narrowed to:
   *     outputType.kind; // 'array'
   *     outputType.itemType; // NumberTypeT
   *     outputType.itemType.kind; // 'number'
   * }
   */
  function verifyType(provided, sample) {
      if (provided.kind === 'array' && sample.kind === 'array') {
          return provided.itemType.kind === sample.itemType.kind && typeof provided.N === 'number';
      }
      return provided.kind === sample.kind;
  }

  // See https://observablehq.com/@mbostock/lab-and-rgb
  const Xn = 0.96422, Yn = 1, Zn = 0.82521, t0 = 4 / 29, t1 = 6 / 29, t2 = 3 * t1 * t1, t3 = t1 * t1 * t1, deg2rad = Math.PI / 180, rad2deg = 180 / Math.PI;
  function constrainAngle(angle) {
      angle = angle % 360;
      if (angle < 0) {
          angle += 360;
      }
      return angle;
  }
  function rgbToLab([r, g, b, alpha]) {
      r = rgb2xyz(r);
      g = rgb2xyz(g);
      b = rgb2xyz(b);
      let x, z;
      const y = xyz2lab((0.2225045 * r + 0.7168786 * g + 0.0606169 * b) / Yn);
      if (r === g && g === b) {
          x = z = y;
      }
      else {
          x = xyz2lab((0.4360747 * r + 0.3850649 * g + 0.1430804 * b) / Xn);
          z = xyz2lab((0.0139322 * r + 0.0971045 * g + 0.7141733 * b) / Zn);
      }
      const l = 116 * y - 16;
      return [(l < 0) ? 0 : l, 500 * (x - y), 200 * (y - z), alpha];
  }
  function rgb2xyz(x) {
      return (x <= 0.04045) ? x / 12.92 : Math.pow((x + 0.055) / 1.055, 2.4);
  }
  function xyz2lab(t) {
      return (t > t3) ? Math.pow(t, 1 / 3) : t / t2 + t0;
  }
  function labToRgb([l, a, b, alpha]) {
      let y = (l + 16) / 116, x = isNaN(a) ? y : y + a / 500, z = isNaN(b) ? y : y - b / 200;
      y = Yn * lab2xyz(y);
      x = Xn * lab2xyz(x);
      z = Zn * lab2xyz(z);
      return [
          xyz2rgb(3.1338561 * x - 1.6168667 * y - 0.4906146 * z),
          xyz2rgb(-0.9787684 * x + 1.9161415 * y + 0.0334540 * z),
          xyz2rgb(0.0719453 * x - 0.2289914 * y + 1.4052427 * z),
          alpha,
      ];
  }
  function xyz2rgb(x) {
      x = (x <= 0.00304) ? 12.92 * x : 1.055 * Math.pow(x, 1 / 2.4) - 0.055;
      return (x < 0) ? 0 : (x > 1) ? 1 : x; // clip to 0..1 range
  }
  function lab2xyz(t) {
      return (t > t1) ? t * t * t : t2 * (t - t0);
  }
  function rgbToHcl(rgbColor) {
      const [l, a, b, alpha] = rgbToLab(rgbColor);
      const c = Math.sqrt(a * a + b * b);
      const h = Math.round(c * 10000) ? constrainAngle(Math.atan2(b, a) * rad2deg) : NaN;
      return [h, c, l, alpha];
  }
  function hclToRgb([h, c, l, alpha]) {
      h = isNaN(h) ? 0 : h * deg2rad;
      return labToRgb([l, Math.cos(h) * c, Math.sin(h) * c, alpha]);
  }
  // https://drafts.csswg.org/css-color-4/#hsl-to-rgb
  function hslToRgb([h, s, l, alpha]) {
      h = constrainAngle(h);
      s /= 100;
      l /= 100;
      function f(n) {
          const k = (n + h / 30) % 12;
          const a = s * Math.min(l, 1 - l);
          return l - a * Math.max(-1, Math.min(k - 3, 9 - k, 1));
      }
      return [f(0), f(8), f(4), alpha];
  }

  /**
   * CSS color parser compliant with CSS Color 4 Specification.
   * Supports: named colors, `transparent` keyword, all rgb hex notations,
   * rgb(), rgba(), hsl() and hsla() functions.
   * Does not round the parsed values to integers from the range 0..255.
   *
   * Syntax:
   *
   * <alpha-value> = <number> | <percentage>
   *         <hue> = <number> | <angle>
   *
   *         rgb() = rgb( <percentage>{3} [ / <alpha-value> ]? ) | rgb( <number>{3} [ / <alpha-value> ]? )
   *         rgb() = rgb( <percentage>#{3} , <alpha-value>? )    | rgb( <number>#{3} , <alpha-value>? )
   *
   *         hsl() = hsl( <hue> <percentage> <percentage> [ / <alpha-value> ]? )
   *         hsl() = hsl( <hue>, <percentage>, <percentage>, <alpha-value>? )
   *
   * Caveats:
   *   - <angle> - <number> with optional `deg` suffix; `grad`, `rad`, `turn` are not supported
   *   - `none` keyword is not supported
   *   - comments inside rgb()/hsl() are not supported
   *   - legacy color syntax rgba() is supported with an identical grammar and behavior to rgb()
   *   - legacy color syntax hsla() is supported with an identical grammar and behavior to hsl()
   *
   * @param input CSS color string to parse.
   * @returns Color in sRGB color space, with `red`, `green`, `blue`
   * and `alpha` channels normalized to the range 0..1,
   * or `undefined` if the input is not a valid color string.
   */
  function parseCssColor(input) {
      input = input.toLowerCase().trim();
      if (input === 'transparent') {
          return [0, 0, 0, 0];
      }
      // 'white', 'black', 'blue'
      const namedColorsMatch = namedColors[input];
      if (namedColorsMatch) {
          const [r, g, b] = namedColorsMatch;
          return [r / 255, g / 255, b / 255, 1];
      }
      // #f0c, #f0cf, #ff00cc, #ff00ccff
      if (input.startsWith('#')) {
          const hexRegexp = /^#(?:[0-9a-f]{3,4}|[0-9a-f]{6}|[0-9a-f]{8})$/;
          if (hexRegexp.test(input)) {
              const step = input.length < 6 ? 1 : 2;
              let i = 1;
              return [
                  parseHex(input.slice(i, i += step)),
                  parseHex(input.slice(i, i += step)),
                  parseHex(input.slice(i, i += step)),
                  parseHex(input.slice(i, i + step) || 'ff'),
              ];
          }
      }
      // rgb(128 0 0), rgb(50% 0% 0%), rgba(255,0,255,0.6), rgb(255 0 255 / 60%), rgb(100% 0% 100% /.6)
      if (input.startsWith('rgb')) {
          const rgbRegExp = /^rgba?\(\s*([\de.+-]+)(%)?(?:\s+|\s*(,)\s*)([\de.+-]+)(%)?(?:\s+|\s*(,)\s*)([\de.+-]+)(%)?(?:\s*([,\/])\s*([\de.+-]+)(%)?)?\s*\)$/;
          const rgbMatch = input.match(rgbRegExp);
          if (rgbMatch) {
              const [_, // eslint-disable-line @typescript-eslint/no-unused-vars
              r, // <numeric>
              rp, // %         (optional)
              f1, // ,         (optional)
              g, // <numeric>
              gp, // %         (optional)
              f2, // ,         (optional)
              b, // <numeric>
              bp, // %         (optional)
              f3, // ,|/       (optional)
              a, // <numeric> (optional)
              ap, // %         (optional)
              ] = rgbMatch;
              const argFormat = [f1 || ' ', f2 || ' ', f3].join('');
              if (argFormat === '  ' ||
                  argFormat === '  /' ||
                  argFormat === ',,' ||
                  argFormat === ',,,') {
                  const valFormat = [rp, gp, bp].join('');
                  const maxValue = (valFormat === '%%%') ? 100 :
                      (valFormat === '') ? 255 : 0;
                  if (maxValue) {
                      const rgba = [
                          clamp(+r / maxValue, 0, 1),
                          clamp(+g / maxValue, 0, 1),
                          clamp(+b / maxValue, 0, 1),
                          a ? parseAlpha(+a, ap) : 1,
                      ];
                      if (validateNumbers(rgba)) {
                          return rgba;
                      }
                      // invalid numbers
                  }
                  // values must be all numbers or all percentages
              }
              return; // comma optional syntax requires no commas at all
          }
      }
      // hsl(120 50% 80%), hsla(120deg,50%,80%,.9), hsl(12e1 50% 80% / 90%)
      const hslRegExp = /^hsla?\(\s*([\de.+-]+)(?:deg)?(?:\s+|\s*(,)\s*)([\de.+-]+)%(?:\s+|\s*(,)\s*)([\de.+-]+)%(?:\s*([,\/])\s*([\de.+-]+)(%)?)?\s*\)$/;
      const hslMatch = input.match(hslRegExp);
      if (hslMatch) {
          const [_, // eslint-disable-line @typescript-eslint/no-unused-vars
          h, // <numeric>
          f1, // ,         (optional)
          s, // <numeric>
          f2, // ,         (optional)
          l, // <numeric>
          f3, // ,|/       (optional)
          a, // <numeric> (optional)
          ap, // %         (optional)
          ] = hslMatch;
          const argFormat = [f1 || ' ', f2 || ' ', f3].join('');
          if (argFormat === '  ' ||
              argFormat === '  /' ||
              argFormat === ',,' ||
              argFormat === ',,,') {
              const hsla = [
                  +h,
                  clamp(+s, 0, 100),
                  clamp(+l, 0, 100),
                  a ? parseAlpha(+a, ap) : 1,
              ];
              if (validateNumbers(hsla)) {
                  return hslToRgb(hsla);
              }
              // invalid numbers
          }
          // comma optional syntax requires no commas at all
      }
  }
  function parseHex(hex) {
      return parseInt(hex.padEnd(2, hex), 16) / 255;
  }
  function parseAlpha(a, asPercentage) {
      return clamp(asPercentage ? (a / 100) : a, 0, 1);
  }
  function clamp(n, min, max) {
      return Math.min(Math.max(min, n), max);
  }
  /**
   * The regular expression for numeric values is not super specific, and it may
   * happen that it will accept a value that is not a valid number. In order to
   * detect and eliminate such values this function exists.
   *
   * @param array Array of uncertain numbers.
   * @returns `true` if the specified array contains only valid numbers, `false` otherwise.
   */
  function validateNumbers(array) {
      return !array.some(Number.isNaN);
  }
  /**
   * To generate:
   * - visit {@link https://www.w3.org/TR/css-color-4/#named-colors}
   * - run in the console:
   * @example
   * copy(`{\n${[...document.querySelector('.named-color-table tbody').children].map((tr) => `${tr.cells[2].textContent.trim()}: [${tr.cells[4].textContent.trim().split(/\s+/).join(', ')}],`).join('\n')}\n}`);
   */
  const namedColors = {
      aliceblue: [240, 248, 255],
      antiquewhite: [250, 235, 215],
      aqua: [0, 255, 255],
      aquamarine: [127, 255, 212],
      azure: [240, 255, 255],
      beige: [245, 245, 220],
      bisque: [255, 228, 196],
      black: [0, 0, 0],
      blanchedalmond: [255, 235, 205],
      blue: [0, 0, 255],
      blueviolet: [138, 43, 226],
      brown: [165, 42, 42],
      burlywood: [222, 184, 135],
      cadetblue: [95, 158, 160],
      chartreuse: [127, 255, 0],
      chocolate: [210, 105, 30],
      coral: [255, 127, 80],
      cornflowerblue: [100, 149, 237],
      cornsilk: [255, 248, 220],
      crimson: [220, 20, 60],
      cyan: [0, 255, 255],
      darkblue: [0, 0, 139],
      darkcyan: [0, 139, 139],
      darkgoldenrod: [184, 134, 11],
      darkgray: [169, 169, 169],
      darkgreen: [0, 100, 0],
      darkgrey: [169, 169, 169],
      darkkhaki: [189, 183, 107],
      darkmagenta: [139, 0, 139],
      darkolivegreen: [85, 107, 47],
      darkorange: [255, 140, 0],
      darkorchid: [153, 50, 204],
      darkred: [139, 0, 0],
      darksalmon: [233, 150, 122],
      darkseagreen: [143, 188, 143],
      darkslateblue: [72, 61, 139],
      darkslategray: [47, 79, 79],
      darkslategrey: [47, 79, 79],
      darkturquoise: [0, 206, 209],
      darkviolet: [148, 0, 211],
      deeppink: [255, 20, 147],
      deepskyblue: [0, 191, 255],
      dimgray: [105, 105, 105],
      dimgrey: [105, 105, 105],
      dodgerblue: [30, 144, 255],
      firebrick: [178, 34, 34],
      floralwhite: [255, 250, 240],
      forestgreen: [34, 139, 34],
      fuchsia: [255, 0, 255],
      gainsboro: [220, 220, 220],
      ghostwhite: [248, 248, 255],
      gold: [255, 215, 0],
      goldenrod: [218, 165, 32],
      gray: [128, 128, 128],
      green: [0, 128, 0],
      greenyellow: [173, 255, 47],
      grey: [128, 128, 128],
      honeydew: [240, 255, 240],
      hotpink: [255, 105, 180],
      indianred: [205, 92, 92],
      indigo: [75, 0, 130],
      ivory: [255, 255, 240],
      khaki: [240, 230, 140],
      lavender: [230, 230, 250],
      lavenderblush: [255, 240, 245],
      lawngreen: [124, 252, 0],
      lemonchiffon: [255, 250, 205],
      lightblue: [173, 216, 230],
      lightcoral: [240, 128, 128],
      lightcyan: [224, 255, 255],
      lightgoldenrodyellow: [250, 250, 210],
      lightgray: [211, 211, 211],
      lightgreen: [144, 238, 144],
      lightgrey: [211, 211, 211],
      lightpink: [255, 182, 193],
      lightsalmon: [255, 160, 122],
      lightseagreen: [32, 178, 170],
      lightskyblue: [135, 206, 250],
      lightslategray: [119, 136, 153],
      lightslategrey: [119, 136, 153],
      lightsteelblue: [176, 196, 222],
      lightyellow: [255, 255, 224],
      lime: [0, 255, 0],
      limegreen: [50, 205, 50],
      linen: [250, 240, 230],
      magenta: [255, 0, 255],
      maroon: [128, 0, 0],
      mediumaquamarine: [102, 205, 170],
      mediumblue: [0, 0, 205],
      mediumorchid: [186, 85, 211],
      mediumpurple: [147, 112, 219],
      mediumseagreen: [60, 179, 113],
      mediumslateblue: [123, 104, 238],
      mediumspringgreen: [0, 250, 154],
      mediumturquoise: [72, 209, 204],
      mediumvioletred: [199, 21, 133],
      midnightblue: [25, 25, 112],
      mintcream: [245, 255, 250],
      mistyrose: [255, 228, 225],
      moccasin: [255, 228, 181],
      navajowhite: [255, 222, 173],
      navy: [0, 0, 128],
      oldlace: [253, 245, 230],
      olive: [128, 128, 0],
      olivedrab: [107, 142, 35],
      orange: [255, 165, 0],
      orangered: [255, 69, 0],
      orchid: [218, 112, 214],
      palegoldenrod: [238, 232, 170],
      palegreen: [152, 251, 152],
      paleturquoise: [175, 238, 238],
      palevioletred: [219, 112, 147],
      papayawhip: [255, 239, 213],
      peachpuff: [255, 218, 185],
      peru: [205, 133, 63],
      pink: [255, 192, 203],
      plum: [221, 160, 221],
      powderblue: [176, 224, 230],
      purple: [128, 0, 128],
      rebeccapurple: [102, 51, 153],
      red: [255, 0, 0],
      rosybrown: [188, 143, 143],
      royalblue: [65, 105, 225],
      saddlebrown: [139, 69, 19],
      salmon: [250, 128, 114],
      sandybrown: [244, 164, 96],
      seagreen: [46, 139, 87],
      seashell: [255, 245, 238],
      sienna: [160, 82, 45],
      silver: [192, 192, 192],
      skyblue: [135, 206, 235],
      slateblue: [106, 90, 205],
      slategray: [112, 128, 144],
      slategrey: [112, 128, 144],
      snow: [255, 250, 250],
      springgreen: [0, 255, 127],
      steelblue: [70, 130, 180],
      tan: [210, 180, 140],
      teal: [0, 128, 128],
      thistle: [216, 191, 216],
      tomato: [255, 99, 71],
      turquoise: [64, 224, 208],
      violet: [238, 130, 238],
      wheat: [245, 222, 179],
      white: [255, 255, 255],
      whitesmoke: [245, 245, 245],
      yellow: [255, 255, 0],
      yellowgreen: [154, 205, 50],
  };

  /**
   * Color representation used by WebGL.
   * Defined in sRGB color space and pre-blended with alpha.
   * @private
   */
  class Color {
      /**
       * @param r Red component premultiplied by `alpha` 0..1
       * @param g Green component premultiplied by `alpha` 0..1
       * @param b Blue component premultiplied by `alpha` 0..1
       * @param [alpha=1] Alpha component 0..1
       * @param [premultiplied=true] Whether the `r`, `g` and `b` values have already
       * been multiplied by alpha. If `true` nothing happens if `false` then they will
       * be multiplied automatically.
       */
      constructor(r, g, b, alpha = 1, premultiplied = true) {
          this.r = r;
          this.g = g;
          this.b = b;
          this.a = alpha;
          if (!premultiplied) {
              this.r *= alpha;
              this.g *= alpha;
              this.b *= alpha;
              if (!alpha) {
                  // alpha = 0 erases completely rgb channels. This behavior is not desirable
                  // if this particular color is later used in color interpolation.
                  // Because of that, a reference to original color is saved.
                  this.overwriteGetter('rgb', [r, g, b, alpha]);
              }
          }
      }
      /**
       * Parses CSS color strings and converts colors to sRGB color space if needed.
       * Officially supported color formats:
       * - keyword, e.g. 'aquamarine' or 'steelblue'
       * - hex (with 3, 4, 6 or 8 digits), e.g. '#f0f' or '#e9bebea9'
       * - rgb and rgba, e.g. 'rgb(0,240,120)' or 'rgba(0%,94%,47%,0.1)' or 'rgb(0 240 120 / .3)'
       * - hsl and hsla, e.g. 'hsl(0,0%,83%)' or 'hsla(0,0%,83%,.5)' or 'hsl(0 0% 83% / 20%)'
       *
       * @param input CSS color string to parse.
       * @returns A `Color` instance, or `undefined` if the input is not a valid color string.
       */
      static parse(input) {
          // in zoom-and-property function input could be an instance of Color class
          if (input instanceof Color) {
              return input;
          }
          if (typeof input !== 'string') {
              return;
          }
          const rgba = parseCssColor(input);
          if (rgba) {
              return new Color(...rgba, false);
          }
      }
      /**
       * Used in color interpolation and by 'to-rgba' expression.
       *
       * @returns Gien color, with reversed alpha blending, in sRGB color space.
       */
      get rgb() {
          const { r, g, b, a } = this;
          const f = a || Infinity; // reverse alpha blending factor
          return this.overwriteGetter('rgb', [r / f, g / f, b / f, a]);
      }
      /**
       * Used in color interpolation.
       *
       * @returns Gien color, with reversed alpha blending, in HCL color space.
       */
      get hcl() {
          return this.overwriteGetter('hcl', rgbToHcl(this.rgb));
      }
      /**
       * Used in color interpolation.
       *
       * @returns Gien color, with reversed alpha blending, in LAB color space.
       */
      get lab() {
          return this.overwriteGetter('lab', rgbToLab(this.rgb));
      }
      /**
       * Lazy getter pattern. When getter is called for the first time lazy value
       * is calculated and then overwrites getter function in given object instance.
       *
       * @example:
       * const redColor = Color.parse('red');
       * let x = redColor.hcl; // this will invoke `get hcl()`, which will calculate
       * // the value of red in HCL space and invoke this `overwriteGetter` function
       * // which in turn will set a field with a key 'hcl' in the `redColor` object.
       * // In other words it will override `get hcl()` from its `Color` prototype
       * // with its own property: hcl = [calculated red value in hcl].
       * let y = redColor.hcl; // next call will no longer invoke getter but simply
       * // return the previously calculated value
       * x === y; // true - `x` is exactly the same object as `y`
       *
       * @param getterKey Getter key
       * @param lazyValue Lazily calculated value to be memoized by current instance
       * @private
       */
      overwriteGetter(getterKey, lazyValue) {
          Object.defineProperty(this, getterKey, { value: lazyValue });
          return lazyValue;
      }
      /**
       * Used by 'to-string' expression.
       *
       * @returns Serialized color in format `rgba(r,g,b,a)`
       * where r,g,b are numbers within 0..255 and alpha is number within 1..0
       *
       * @example
       * var purple = new Color.parse('purple');
       * purple.toString; // = "rgba(128,0,128,1)"
       * var translucentGreen = new Color.parse('rgba(26, 207, 26, .73)');
       * translucentGreen.toString(); // = "rgba(26,207,26,0.73)"
       */
      toString() {
          const [r, g, b, a] = this.rgb;
          return `rgba(${[r, g, b].map(n => Math.round(n * 255)).join(',')},${a})`;
      }
  }
  Color.black = new Color(0, 0, 0, 1);
  Color.white = new Color(1, 1, 1, 1);
  Color.transparent = new Color(0, 0, 0, 0);
  Color.red = new Color(1, 0, 0, 1);

  // Flow type declarations for Intl cribbed from
  // https://github.com/facebook/flow/issues/1270
  class Collator {
      constructor(caseSensitive, diacriticSensitive, locale) {
          if (caseSensitive)
              this.sensitivity = diacriticSensitive ? 'variant' : 'case';
          else
              this.sensitivity = diacriticSensitive ? 'accent' : 'base';
          this.locale = locale;
          this.collator = new Intl.Collator(this.locale ? this.locale : [], { sensitivity: this.sensitivity, usage: 'search' });
      }
      compare(lhs, rhs) {
          return this.collator.compare(lhs, rhs);
      }
      resolvedLocale() {
          // We create a Collator without "usage: search" because we don't want
          // the search options encoded in our result (e.g. "en-u-co-search")
          return new Intl.Collator(this.locale ? this.locale : [])
              .resolvedOptions().locale;
      }
  }

  class FormattedSection {
      constructor(text, image, scale, fontStack, textColor) {
          this.text = text;
          this.image = image;
          this.scale = scale;
          this.fontStack = fontStack;
          this.textColor = textColor;
      }
  }
  class Formatted {
      constructor(sections) {
          this.sections = sections;
      }
      static fromString(unformatted) {
          return new Formatted([new FormattedSection(unformatted, null, null, null, null)]);
      }
      isEmpty() {
          if (this.sections.length === 0)
              return true;
          return !this.sections.some(section => section.text.length !== 0 ||
              (section.image && section.image.name.length !== 0));
      }
      static factory(text) {
          if (text instanceof Formatted) {
              return text;
          }
          else {
              return Formatted.fromString(text);
          }
      }
      toString() {
          if (this.sections.length === 0)
              return '';
          return this.sections.map(section => section.text).join('');
      }
  }

  /**
   * A set of four numbers representing padding around a box. Create instances from
   * bare arrays or numeric values using the static method `Padding.parse`.
   * @private
   */
  class Padding {
      constructor(values) {
          this.values = values.slice();
      }
      /**
       * Numeric padding values
       * @param input A padding value
       * @returns A `Padding` instance, or `undefined` if the input is not a valid padding value.
       */
      static parse(input) {
          if (input instanceof Padding) {
              return input;
          }
          // Backwards compatibility: bare number is treated the same as array with single value.
          // Padding applies to all four sides.
          if (typeof input === 'number') {
              return new Padding([input, input, input, input]);
          }
          if (!Array.isArray(input)) {
              return undefined;
          }
          if (input.length < 1 || input.length > 4) {
              return undefined;
          }
          for (const val of input) {
              if (typeof val !== 'number') {
                  return undefined;
              }
          }
          // Expand shortcut properties into explicit 4-sided values
          switch (input.length) {
              case 1:
                  input = [input[0], input[0], input[0], input[0]];
                  break;
              case 2:
                  input = [input[0], input[1], input[0], input[1]];
                  break;
              case 3:
                  input = [input[0], input[1], input[2], input[1]];
                  break;
          }
          return new Padding(input);
      }
      toString() {
          return JSON.stringify(this.values);
      }
  }

  /** Set of valid anchor positions, as a set for validation */
  const anchors = new Set(['center', 'left', 'right', 'top', 'bottom', 'top-left', 'top-right', 'bottom-left', 'bottom-right']);
  /**
   * Utility class to assist managing values for text-variable-anchor-offset property. Create instances from
   * bare arrays using the static method `VariableAnchorOffsetCollection.parse`.
   * @private
   */
  class VariableAnchorOffsetCollection {
      constructor(values) {
          this.values = values.slice();
      }
      static parse(input) {
          if (input instanceof VariableAnchorOffsetCollection) {
              return input;
          }
          if (!Array.isArray(input) ||
              input.length < 1 ||
              input.length % 2 !== 0) {
              return undefined;
          }
          for (let i = 0; i < input.length; i += 2) {
              // Elements in even positions should be anchor positions; Elements in odd positions should be offset values
              const anchorValue = input[i];
              const offsetValue = input[i + 1];
              if (typeof anchorValue !== 'string' || !anchors.has(anchorValue)) {
                  return undefined;
              }
              if (!Array.isArray(offsetValue) || offsetValue.length !== 2 || typeof offsetValue[0] !== 'number' || typeof offsetValue[1] !== 'number') {
                  return undefined;
              }
          }
          return new VariableAnchorOffsetCollection(input);
      }
      toString() {
          return JSON.stringify(this.values);
      }
  }

  class ResolvedImage {
      constructor(options) {
          this.name = options.name;
          this.available = options.available;
      }
      toString() {
          return this.name;
      }
      static fromString(name) {
          if (!name)
              return null; // treat empty values as no image
          return new ResolvedImage({ name, available: false });
      }
  }

  function validateRGBA(r, g, b, a) {
      if (!(typeof r === 'number' && r >= 0 && r <= 255 &&
          typeof g === 'number' && g >= 0 && g <= 255 &&
          typeof b === 'number' && b >= 0 && b <= 255)) {
          const value = typeof a === 'number' ? [r, g, b, a] : [r, g, b];
          return `Invalid rgba value [${value.join(', ')}]: 'r', 'g', and 'b' must be between 0 and 255.`;
      }
      if (!(typeof a === 'undefined' || (typeof a === 'number' && a >= 0 && a <= 1))) {
          return `Invalid rgba value [${[r, g, b, a].join(', ')}]: 'a' must be between 0 and 1.`;
      }
      return null;
  }
  function isValue(mixed) {
      if (mixed === null ||
          typeof mixed === 'string' ||
          typeof mixed === 'boolean' ||
          typeof mixed === 'number' ||
          mixed instanceof Color ||
          mixed instanceof Collator ||
          mixed instanceof Formatted ||
          mixed instanceof Padding ||
          mixed instanceof VariableAnchorOffsetCollection ||
          mixed instanceof ResolvedImage) {
          return true;
      }
      else if (Array.isArray(mixed)) {
          for (const item of mixed) {
              if (!isValue(item)) {
                  return false;
              }
          }
          return true;
      }
      else if (typeof mixed === 'object') {
          for (const key in mixed) {
              if (!isValue(mixed[key])) {
                  return false;
              }
          }
          return true;
      }
      else {
          return false;
      }
  }
  function typeOf(value) {
      if (value === null) {
          return NullType;
      }
      else if (typeof value === 'string') {
          return StringType;
      }
      else if (typeof value === 'boolean') {
          return BooleanType;
      }
      else if (typeof value === 'number') {
          return NumberType;
      }
      else if (value instanceof Color) {
          return ColorType;
      }
      else if (value instanceof Collator) {
          return CollatorType;
      }
      else if (value instanceof Formatted) {
          return FormattedType;
      }
      else if (value instanceof Padding) {
          return PaddingType;
      }
      else if (value instanceof VariableAnchorOffsetCollection) {
          return VariableAnchorOffsetCollectionType;
      }
      else if (value instanceof ResolvedImage) {
          return ResolvedImageType;
      }
      else if (Array.isArray(value)) {
          const length = value.length;
          let itemType;
          for (const item of value) {
              const t = typeOf(item);
              if (!itemType) {
                  itemType = t;
              }
              else if (itemType === t) {
                  continue;
              }
              else {
                  itemType = ValueType;
                  break;
              }
          }
          return array$1(itemType || ValueType, length);
      }
      else {
          return ObjectType;
      }
  }
  function toString(value) {
      const type = typeof value;
      if (value === null) {
          return '';
      }
      else if (type === 'string' || type === 'number' || type === 'boolean') {
          return String(value);
      }
      else if (value instanceof Color || value instanceof Formatted || value instanceof Padding || value instanceof VariableAnchorOffsetCollection || value instanceof ResolvedImage) {
          return value.toString();
      }
      else {
          return JSON.stringify(value);
      }
  }

  class Literal {
      constructor(type, value) {
          this.type = type;
          this.value = value;
      }
      static parse(args, context) {
          if (args.length !== 2)
              return context.error(`'literal' expression requires exactly one argument, but found ${args.length - 1} instead.`);
          if (!isValue(args[1]))
              return context.error('invalid value');
          const value = args[1];
          let type = typeOf(value);
          // special case: infer the item type if possible for zero-length arrays
          const expected = context.expectedType;
          if (type.kind === 'array' &&
              type.N === 0 &&
              expected &&
              expected.kind === 'array' &&
              (typeof expected.N !== 'number' || expected.N === 0)) {
              type = expected;
          }
          return new Literal(type, value);
      }
      evaluate() {
          return this.value;
      }
      eachChild() { }
      outputDefined() {
          return true;
      }
  }

  class RuntimeError {
      constructor(message) {
          this.name = 'ExpressionEvaluationError';
          this.message = message;
      }
      toJSON() {
          return this.message;
      }
  }

  const types$1 = {
      string: StringType,
      number: NumberType,
      boolean: BooleanType,
      object: ObjectType
  };
  class Assertion {
      constructor(type, args) {
          this.type = type;
          this.args = args;
      }
      static parse(args, context) {
          if (args.length < 2)
              return context.error('Expected at least one argument.');
          let i = 1;
          let type;
          const name = args[0];
          if (name === 'array') {
              let itemType;
              if (args.length > 2) {
                  const type = args[1];
                  if (typeof type !== 'string' || !(type in types$1) || type === 'object')
                      return context.error('The item type argument of "array" must be one of string, number, boolean', 1);
                  itemType = types$1[type];
                  i++;
              }
              else {
                  itemType = ValueType;
              }
              let N;
              if (args.length > 3) {
                  if (args[2] !== null &&
                      (typeof args[2] !== 'number' ||
                          args[2] < 0 ||
                          args[2] !== Math.floor(args[2]))) {
                      return context.error('The length argument to "array" must be a positive integer literal', 2);
                  }
                  N = args[2];
                  i++;
              }
              type = array$1(itemType, N);
          }
          else {
              if (!types$1[name])
                  throw new Error(`Types doesn't contain name = ${name}`);
              type = types$1[name];
          }
          const parsed = [];
          for (; i < args.length; i++) {
              const input = context.parse(args[i], i, ValueType);
              if (!input)
                  return null;
              parsed.push(input);
          }
          return new Assertion(type, parsed);
      }
      evaluate(ctx) {
          for (let i = 0; i < this.args.length; i++) {
              const value = this.args[i].evaluate(ctx);
              const error = checkSubtype(this.type, typeOf(value));
              if (!error) {
                  return value;
              }
              else if (i === this.args.length - 1) {
                  throw new RuntimeError(`Expected value to be of type ${toString$1(this.type)}, but found ${toString$1(typeOf(value))} instead.`);
              }
          }
          throw new Error();
      }
      eachChild(fn) {
          this.args.forEach(fn);
      }
      outputDefined() {
          return this.args.every(arg => arg.outputDefined());
      }
  }

  const types = {
      'to-boolean': BooleanType,
      'to-color': ColorType,
      'to-number': NumberType,
      'to-string': StringType
  };
  /**
   * Special form for error-coalescing coercion expressions "to-number",
   * "to-color".  Since these coercions can fail at runtime, they accept multiple
   * arguments, only evaluating one at a time until one succeeds.
   *
   * @private
   */
  class Coercion {
      constructor(type, args) {
          this.type = type;
          this.args = args;
      }
      static parse(args, context) {
          if (args.length < 2)
              return context.error('Expected at least one argument.');
          const name = args[0];
          if (!types[name])
              throw new Error(`Can't parse ${name} as it is not part of the known types`);
          if ((name === 'to-boolean' || name === 'to-string') && args.length !== 2)
              return context.error('Expected one argument.');
          const type = types[name];
          const parsed = [];
          for (let i = 1; i < args.length; i++) {
              const input = context.parse(args[i], i, ValueType);
              if (!input)
                  return null;
              parsed.push(input);
          }
          return new Coercion(type, parsed);
      }
      evaluate(ctx) {
          switch (this.type.kind) {
              case 'boolean':
                  return Boolean(this.args[0].evaluate(ctx));
              case 'color': {
                  let input;
                  let error;
                  for (const arg of this.args) {
                      input = arg.evaluate(ctx);
                      error = null;
                      if (input instanceof Color) {
                          return input;
                      }
                      else if (typeof input === 'string') {
                          const c = ctx.parseColor(input);
                          if (c)
                              return c;
                      }
                      else if (Array.isArray(input)) {
                          if (input.length < 3 || input.length > 4) {
                              error = `Invalid rbga value ${JSON.stringify(input)}: expected an array containing either three or four numeric values.`;
                          }
                          else {
                              error = validateRGBA(input[0], input[1], input[2], input[3]);
                          }
                          if (!error) {
                              return new Color(input[0] / 255, input[1] / 255, input[2] / 255, input[3]);
                          }
                      }
                  }
                  throw new RuntimeError(error || `Could not parse color from value '${typeof input === 'string' ? input : JSON.stringify(input)}'`);
              }
              case 'padding': {
                  let input;
                  for (const arg of this.args) {
                      input = arg.evaluate(ctx);
                      const pad = Padding.parse(input);
                      if (pad) {
                          return pad;
                      }
                  }
                  throw new RuntimeError(`Could not parse padding from value '${typeof input === 'string' ? input : JSON.stringify(input)}'`);
              }
              case 'variableAnchorOffsetCollection': {
                  let input;
                  for (const arg of this.args) {
                      input = arg.evaluate(ctx);
                      const coll = VariableAnchorOffsetCollection.parse(input);
                      if (coll) {
                          return coll;
                      }
                  }
                  throw new RuntimeError(`Could not parse variableAnchorOffsetCollection from value '${typeof input === 'string' ? input : JSON.stringify(input)}'`);
              }
              case 'number': {
                  let value = null;
                  for (const arg of this.args) {
                      value = arg.evaluate(ctx);
                      if (value === null)
                          return 0;
                      const num = Number(value);
                      if (isNaN(num))
                          continue;
                      return num;
                  }
                  throw new RuntimeError(`Could not convert ${JSON.stringify(value)} to number.`);
              }
              case 'formatted':
                  // There is no explicit 'to-formatted' but this coercion can be implicitly
                  // created by properties that expect the 'formatted' type.
                  return Formatted.fromString(toString(this.args[0].evaluate(ctx)));
              case 'resolvedImage':
                  return ResolvedImage.fromString(toString(this.args[0].evaluate(ctx)));
              default:
                  return toString(this.args[0].evaluate(ctx));
          }
      }
      eachChild(fn) {
          this.args.forEach(fn);
      }
      outputDefined() {
          return this.args.every(arg => arg.outputDefined());
      }
  }

  const geometryTypes = ['Unknown', 'Point', 'LineString', 'Polygon'];
  class EvaluationContext {
      constructor() {
          this.globals = null;
          this.feature = null;
          this.featureState = null;
          this.formattedSection = null;
          this._parseColorCache = {};
          this.availableImages = null;
          this.canonical = null;
      }
      id() {
          return this.feature && 'id' in this.feature ? this.feature.id : null;
      }
      geometryType() {
          return this.feature ? typeof this.feature.type === 'number' ? geometryTypes[this.feature.type] : this.feature.type : null;
      }
      geometry() {
          return this.feature && 'geometry' in this.feature ? this.feature.geometry : null;
      }
      canonicalID() {
          return this.canonical;
      }
      properties() {
          return this.feature && this.feature.properties || {};
      }
      parseColor(input) {
          let cached = this._parseColorCache[input];
          if (!cached) {
              cached = this._parseColorCache[input] = Color.parse(input);
          }
          return cached;
      }
  }

  /**
   * State associated parsing at a given point in an expression tree.
   * @private
   */
  class ParsingContext {
      constructor(registry, isConstantFunc, path = [], expectedType, scope = new Scope(), errors = []) {
          this.registry = registry;
          this.path = path;
          this.key = path.map(part => `[${part}]`).join('');
          this.scope = scope;
          this.errors = errors;
          this.expectedType = expectedType;
          this._isConstant = isConstantFunc;
      }
      /**
       * @param expr the JSON expression to parse
       * @param index the optional argument index if this expression is an argument of a parent expression that's being parsed
       * @param options
       * @param options.omitTypeAnnotations set true to omit inferred type annotations.  Caller beware: with this option set, the parsed expression's type will NOT satisfy `expectedType` if it would normally be wrapped in an inferred annotation.
       * @private
       */
      parse(expr, index, expectedType, bindings, options = {}) {
          if (index) {
              return this.concat(index, expectedType, bindings)._parse(expr, options);
          }
          return this._parse(expr, options);
      }
      _parse(expr, options) {
          if (expr === null || typeof expr === 'string' || typeof expr === 'boolean' || typeof expr === 'number') {
              expr = ['literal', expr];
          }
          function annotate(parsed, type, typeAnnotation) {
              if (typeAnnotation === 'assert') {
                  return new Assertion(type, [parsed]);
              }
              else if (typeAnnotation === 'coerce') {
                  return new Coercion(type, [parsed]);
              }
              else {
                  return parsed;
              }
          }
          if (Array.isArray(expr)) {
              if (expr.length === 0) {
                  return this.error('Expected an array with at least one element. If you wanted a literal array, use ["literal", []].');
              }
              const op = expr[0];
              if (typeof op !== 'string') {
                  this.error(`Expression name must be a string, but found ${typeof op} instead. If you wanted a literal array, use ["literal", [...]].`, 0);
                  return null;
              }
              const Expr = this.registry[op];
              if (Expr) {
                  let parsed = Expr.parse(expr, this);
                  if (!parsed)
                      return null;
                  if (this.expectedType) {
                      const expected = this.expectedType;
                      const actual = parsed.type;
                      // When we expect a number, string, boolean, or array but have a value, wrap it in an assertion.
                      // When we expect a color or formatted string, but have a string or value, wrap it in a coercion.
                      // Otherwise, we do static type-checking.
                      //
                      // These behaviors are overridable for:
                      //   * The "coalesce" operator, which needs to omit type annotations.
                      //   * String-valued properties (e.g. `text-field`), where coercion is more convenient than assertion.
                      //
                      if ((expected.kind === 'string' || expected.kind === 'number' || expected.kind === 'boolean' || expected.kind === 'object' || expected.kind === 'array') && actual.kind === 'value') {
                          parsed = annotate(parsed, expected, options.typeAnnotation || 'assert');
                      }
                      else if ((expected.kind === 'color' || expected.kind === 'formatted' || expected.kind === 'resolvedImage') && (actual.kind === 'value' || actual.kind === 'string')) {
                          parsed = annotate(parsed, expected, options.typeAnnotation || 'coerce');
                      }
                      else if (expected.kind === 'padding' && (actual.kind === 'value' || actual.kind === 'number' || actual.kind === 'array')) {
                          parsed = annotate(parsed, expected, options.typeAnnotation || 'coerce');
                      }
                      else if (expected.kind === 'variableAnchorOffsetCollection' && (actual.kind === 'value' || actual.kind === 'array')) {
                          parsed = annotate(parsed, expected, options.typeAnnotation || 'coerce');
                      }
                      else if (this.checkSubtype(expected, actual)) {
                          return null;
                      }
                  }
                  // If an expression's arguments are all literals, we can evaluate
                  // it immediately and replace it with a literal value in the
                  // parsed/compiled result. Expressions that expect an image should
                  // not be resolved here so we can later get the available images.
                  if (!(parsed instanceof Literal) && (parsed.type.kind !== 'resolvedImage') && this._isConstant(parsed)) {
                      const ec = new EvaluationContext();
                      try {
                          parsed = new Literal(parsed.type, parsed.evaluate(ec));
                      }
                      catch (e) {
                          this.error(e.message);
                          return null;
                      }
                  }
                  return parsed;
              }
              return this.error(`Unknown expression "${op}". If you wanted a literal array, use ["literal", [...]].`, 0);
          }
          else if (typeof expr === 'undefined') {
              return this.error('\'undefined\' value invalid. Use null instead.');
          }
          else if (typeof expr === 'object') {
              return this.error('Bare objects invalid. Use ["literal", {...}] instead.');
          }
          else {
              return this.error(`Expected an array, but found ${typeof expr} instead.`);
          }
      }
      /**
       * Returns a copy of this context suitable for parsing the subexpression at
       * index `index`, optionally appending to 'let' binding map.
       *
       * Note that `errors` property, intended for collecting errors while
       * parsing, is copied by reference rather than cloned.
       * @private
       */
      concat(index, expectedType, bindings) {
          const path = typeof index === 'number' ? this.path.concat(index) : this.path;
          const scope = bindings ? this.scope.concat(bindings) : this.scope;
          return new ParsingContext(this.registry, this._isConstant, path, expectedType || null, scope, this.errors);
      }
      /**
       * Push a parsing (or type checking) error into the `this.errors`
       * @param error The message
       * @param keys Optionally specify the source of the error at a child
       * of the current expression at `this.key`.
       * @private
       */
      error(error, ...keys) {
          const key = `${this.key}${keys.map(k => `[${k}]`).join('')}`;
          this.errors.push(new ExpressionParsingError(key, error));
      }
      /**
       * Returns null if `t` is a subtype of `expected`; otherwise returns an
       * error message and also pushes it to `this.errors`.
       * @param expected The expected type
       * @param t The actual type
       * @returns null if `t` is a subtype of `expected`; otherwise returns an error message
       */
      checkSubtype(expected, t) {
          const error = checkSubtype(expected, t);
          if (error)
              this.error(error);
          return error;
      }
  }

  class CollatorExpression {
      constructor(caseSensitive, diacriticSensitive, locale) {
          this.type = CollatorType;
          this.locale = locale;
          this.caseSensitive = caseSensitive;
          this.diacriticSensitive = diacriticSensitive;
      }
      static parse(args, context) {
          if (args.length !== 2)
              return context.error('Expected one argument.');
          const options = args[1];
          if (typeof options !== 'object' || Array.isArray(options))
              return context.error('Collator options argument must be an object.');
          const caseSensitive = context.parse(options['case-sensitive'] === undefined ? false : options['case-sensitive'], 1, BooleanType);
          if (!caseSensitive)
              return null;
          const diacriticSensitive = context.parse(options['diacritic-sensitive'] === undefined ? false : options['diacritic-sensitive'], 1, BooleanType);
          if (!diacriticSensitive)
              return null;
          let locale = null;
          if (options['locale']) {
              locale = context.parse(options['locale'], 1, StringType);
              if (!locale)
                  return null;
          }
          return new CollatorExpression(caseSensitive, diacriticSensitive, locale);
      }
      evaluate(ctx) {
          return new Collator(this.caseSensitive.evaluate(ctx), this.diacriticSensitive.evaluate(ctx), this.locale ? this.locale.evaluate(ctx) : null);
      }
      eachChild(fn) {
          fn(this.caseSensitive);
          fn(this.diacriticSensitive);
          if (this.locale) {
              fn(this.locale);
          }
      }
      outputDefined() {
          // Technically the set of possible outputs is the combinatoric set of Collators produced
          // by all possible outputs of locale/caseSensitive/diacriticSensitive
          // But for the primary use of Collators in comparison operators, we ignore the Collator's
          // possible outputs anyway, so we can get away with leaving this false for now.
          return false;
      }
  }

  const EXTENT = 8192;
  function updateBBox(bbox, coord) {
      bbox[0] = Math.min(bbox[0], coord[0]);
      bbox[1] = Math.min(bbox[1], coord[1]);
      bbox[2] = Math.max(bbox[2], coord[0]);
      bbox[3] = Math.max(bbox[3], coord[1]);
  }
  function mercatorXfromLng(lng) {
      return (180 + lng) / 360;
  }
  function mercatorYfromLat(lat) {
      return (180 - (180 / Math.PI * Math.log(Math.tan(Math.PI / 4 + lat * Math.PI / 360)))) / 360;
  }
  function boxWithinBox(bbox1, bbox2) {
      if (bbox1[0] <= bbox2[0])
          return false;
      if (bbox1[2] >= bbox2[2])
          return false;
      if (bbox1[1] <= bbox2[1])
          return false;
      if (bbox1[3] >= bbox2[3])
          return false;
      return true;
  }
  function getTileCoordinates(p, canonical) {
      const x = mercatorXfromLng(p[0]);
      const y = mercatorYfromLat(p[1]);
      const tilesAtZoom = Math.pow(2, canonical.z);
      return [Math.round(x * tilesAtZoom * EXTENT), Math.round(y * tilesAtZoom * EXTENT)];
  }
  function onBoundary(p, p1, p2) {
      const x1 = p[0] - p1[0];
      const y1 = p[1] - p1[1];
      const x2 = p[0] - p2[0];
      const y2 = p[1] - p2[1];
      return (x1 * y2 - x2 * y1 === 0) && (x1 * x2 <= 0) && (y1 * y2 <= 0);
  }
  function rayIntersect(p, p1, p2) {
      return ((p1[1] > p[1]) !== (p2[1] > p[1])) && (p[0] < (p2[0] - p1[0]) * (p[1] - p1[1]) / (p2[1] - p1[1]) + p1[0]);
  }
  // ray casting algorithm for detecting if point is in polygon
  function pointWithinPolygon(point, rings) {
      let inside = false;
      for (let i = 0, len = rings.length; i < len; i++) {
          const ring = rings[i];
          for (let j = 0, len2 = ring.length; j < len2 - 1; j++) {
              if (onBoundary(point, ring[j], ring[j + 1]))
                  return false;
              if (rayIntersect(point, ring[j], ring[j + 1]))
                  inside = !inside;
          }
      }
      return inside;
  }
  function pointWithinPolygons(point, polygons) {
      for (let i = 0; i < polygons.length; i++) {
          if (pointWithinPolygon(point, polygons[i]))
              return true;
      }
      return false;
  }
  function perp(v1, v2) {
      return (v1[0] * v2[1] - v1[1] * v2[0]);
  }
  // check if p1 and p2 are in different sides of line segment q1->q2
  function twoSided(p1, p2, q1, q2) {
      // q1->p1 (x1, y1), q1->p2 (x2, y2), q1->q2 (x3, y3)
      const x1 = p1[0] - q1[0];
      const y1 = p1[1] - q1[1];
      const x2 = p2[0] - q1[0];
      const y2 = p2[1] - q1[1];
      const x3 = q2[0] - q1[0];
      const y3 = q2[1] - q1[1];
      const det1 = (x1 * y3 - x3 * y1);
      const det2 = (x2 * y3 - x3 * y2);
      if ((det1 > 0 && det2 < 0) || (det1 < 0 && det2 > 0))
          return true;
      return false;
  }
  // a, b are end points for line segment1, c and d are end points for line segment2
  function lineIntersectLine(a, b, c, d) {
      // check if two segments are parallel or not
      // precondition is end point a, b is inside polygon, if line a->b is
      // parallel to polygon edge c->d, then a->b won't intersect with c->d
      const vectorP = [b[0] - a[0], b[1] - a[1]];
      const vectorQ = [d[0] - c[0], d[1] - c[1]];
      if (perp(vectorQ, vectorP) === 0)
          return false;
      // If lines are intersecting with each other, the relative location should be:
      // a and b lie in different sides of segment c->d
      // c and d lie in different sides of segment a->b
      if (twoSided(a, b, c, d) && twoSided(c, d, a, b))
          return true;
      return false;
  }
  function lineIntersectPolygon(p1, p2, polygon) {
      for (const ring of polygon) {
          // loop through every edge of the ring
          for (let j = 0; j < ring.length - 1; ++j) {
              if (lineIntersectLine(p1, p2, ring[j], ring[j + 1])) {
                  return true;
              }
          }
      }
      return false;
  }
  function lineStringWithinPolygon(line, polygon) {
      // First, check if geometry points of line segments are all inside polygon
      for (let i = 0; i < line.length; ++i) {
          if (!pointWithinPolygon(line[i], polygon)) {
              return false;
          }
      }
      // Second, check if there is line segment intersecting polygon edge
      for (let i = 0; i < line.length - 1; ++i) {
          if (lineIntersectPolygon(line[i], line[i + 1], polygon)) {
              return false;
          }
      }
      return true;
  }
  function lineStringWithinPolygons(line, polygons) {
      for (let i = 0; i < polygons.length; i++) {
          if (lineStringWithinPolygon(line, polygons[i]))
              return true;
      }
      return false;
  }
  function getTilePolygon(coordinates, bbox, canonical) {
      const polygon = [];
      for (let i = 0; i < coordinates.length; i++) {
          const ring = [];
          for (let j = 0; j < coordinates[i].length; j++) {
              const coord = getTileCoordinates(coordinates[i][j], canonical);
              updateBBox(bbox, coord);
              ring.push(coord);
          }
          polygon.push(ring);
      }
      return polygon;
  }
  function getTilePolygons(coordinates, bbox, canonical) {
      const polygons = [];
      for (let i = 0; i < coordinates.length; i++) {
          const polygon = getTilePolygon(coordinates[i], bbox, canonical);
          polygons.push(polygon);
      }
      return polygons;
  }
  function updatePoint(p, bbox, polyBBox, worldSize) {
      if (p[0] < polyBBox[0] || p[0] > polyBBox[2]) {
          const halfWorldSize = worldSize * 0.5;
          let shift = (p[0] - polyBBox[0] > halfWorldSize) ? -worldSize : (polyBBox[0] - p[0] > halfWorldSize) ? worldSize : 0;
          if (shift === 0) {
              shift = (p[0] - polyBBox[2] > halfWorldSize) ? -worldSize : (polyBBox[2] - p[0] > halfWorldSize) ? worldSize : 0;
          }
          p[0] += shift;
      }
      updateBBox(bbox, p);
  }
  function resetBBox(bbox) {
      bbox[0] = bbox[1] = Infinity;
      bbox[2] = bbox[3] = -Infinity;
  }
  function getTilePoints(geometry, pointBBox, polyBBox, canonical) {
      const worldSize = Math.pow(2, canonical.z) * EXTENT;
      const shifts = [canonical.x * EXTENT, canonical.y * EXTENT];
      const tilePoints = [];
      for (const points of geometry) {
          for (const point of points) {
              const p = [point.x + shifts[0], point.y + shifts[1]];
              updatePoint(p, pointBBox, polyBBox, worldSize);
              tilePoints.push(p);
          }
      }
      return tilePoints;
  }
  function getTileLines(geometry, lineBBox, polyBBox, canonical) {
      const worldSize = Math.pow(2, canonical.z) * EXTENT;
      const shifts = [canonical.x * EXTENT, canonical.y * EXTENT];
      const tileLines = [];
      for (const line of geometry) {
          const tileLine = [];
          for (const point of line) {
              const p = [point.x + shifts[0], point.y + shifts[1]];
              updateBBox(lineBBox, p);
              tileLine.push(p);
          }
          tileLines.push(tileLine);
      }
      if (lineBBox[2] - lineBBox[0] <= worldSize / 2) {
          resetBBox(lineBBox);
          for (const line of tileLines) {
              for (const p of line) {
                  updatePoint(p, lineBBox, polyBBox, worldSize);
              }
          }
      }
      return tileLines;
  }
  function pointsWithinPolygons(ctx, polygonGeometry) {
      const pointBBox = [Infinity, Infinity, -Infinity, -Infinity];
      const polyBBox = [Infinity, Infinity, -Infinity, -Infinity];
      const canonical = ctx.canonicalID();
      if (polygonGeometry.type === 'Polygon') {
          const tilePolygon = getTilePolygon(polygonGeometry.coordinates, polyBBox, canonical);
          const tilePoints = getTilePoints(ctx.geometry(), pointBBox, polyBBox, canonical);
          if (!boxWithinBox(pointBBox, polyBBox))
              return false;
          for (const point of tilePoints) {
              if (!pointWithinPolygon(point, tilePolygon))
                  return false;
          }
      }
      if (polygonGeometry.type === 'MultiPolygon') {
          const tilePolygons = getTilePolygons(polygonGeometry.coordinates, polyBBox, canonical);
          const tilePoints = getTilePoints(ctx.geometry(), pointBBox, polyBBox, canonical);
          if (!boxWithinBox(pointBBox, polyBBox))
              return false;
          for (const point of tilePoints) {
              if (!pointWithinPolygons(point, tilePolygons))
                  return false;
          }
      }
      return true;
  }
  function linesWithinPolygons(ctx, polygonGeometry) {
      const lineBBox = [Infinity, Infinity, -Infinity, -Infinity];
      const polyBBox = [Infinity, Infinity, -Infinity, -Infinity];
      const canonical = ctx.canonicalID();
      if (polygonGeometry.type === 'Polygon') {
          const tilePolygon = getTilePolygon(polygonGeometry.coordinates, polyBBox, canonical);
          const tileLines = getTileLines(ctx.geometry(), lineBBox, polyBBox, canonical);
          if (!boxWithinBox(lineBBox, polyBBox))
              return false;
          for (const line of tileLines) {
              if (!lineStringWithinPolygon(line, tilePolygon))
                  return false;
          }
      }
      if (polygonGeometry.type === 'MultiPolygon') {
          const tilePolygons = getTilePolygons(polygonGeometry.coordinates, polyBBox, canonical);
          const tileLines = getTileLines(ctx.geometry(), lineBBox, polyBBox, canonical);
          if (!boxWithinBox(lineBBox, polyBBox))
              return false;
          for (const line of tileLines) {
              if (!lineStringWithinPolygons(line, tilePolygons))
                  return false;
          }
      }
      return true;
  }
  class Within {
      constructor(geojson, geometries) {
          this.type = BooleanType;
          this.geojson = geojson;
          this.geometries = geometries;
      }
      static parse(args, context) {
          if (args.length !== 2)
              return context.error(`'within' expression requires exactly one argument, but found ${args.length - 1} instead.`);
          if (isValue(args[1])) {
              const geojson = args[1];
              if (geojson.type === 'FeatureCollection') {
                  for (let i = 0; i < geojson.features.length; ++i) {
                      const type = geojson.features[i].geometry.type;
                      if (type === 'Polygon' || type === 'MultiPolygon') {
                          return new Within(geojson, geojson.features[i].geometry);
                      }
                  }
              }
              else if (geojson.type === 'Feature') {
                  const type = geojson.geometry.type;
                  if (type === 'Polygon' || type === 'MultiPolygon') {
                      return new Within(geojson, geojson.geometry);
                  }
              }
              else if (geojson.type === 'Polygon' || geojson.type === 'MultiPolygon') {
                  return new Within(geojson, geojson);
              }
          }
          return context.error('\'within\' expression requires valid geojson object that contains polygon geometry type.');
      }
      evaluate(ctx) {
          if (ctx.geometry() != null && ctx.canonicalID() != null) {
              if (ctx.geometryType() === 'Point') {
                  return pointsWithinPolygons(ctx, this.geometries);
              }
              else if (ctx.geometryType() === 'LineString') {
                  return linesWithinPolygons(ctx, this.geometries);
              }
          }
          return false;
      }
      eachChild() { }
      outputDefined() {
          return true;
      }
  }

  class Var {
      constructor(name, boundExpression) {
          this.type = boundExpression.type;
          this.name = name;
          this.boundExpression = boundExpression;
      }
      static parse(args, context) {
          if (args.length !== 2 || typeof args[1] !== 'string')
              return context.error('\'var\' expression requires exactly one string literal argument.');
          const name = args[1];
          if (!context.scope.has(name)) {
              return context.error(`Unknown variable "${name}". Make sure "${name}" has been bound in an enclosing "let" expression before using it.`, 1);
          }
          return new Var(name, context.scope.get(name));
      }
      evaluate(ctx) {
          return this.boundExpression.evaluate(ctx);
      }
      eachChild() { }
      outputDefined() {
          return false;
      }
  }

  class CompoundExpression {
      constructor(name, type, evaluate, args) {
          this.name = name;
          this.type = type;
          this._evaluate = evaluate;
          this.args = args;
      }
      evaluate(ctx) {
          return this._evaluate(ctx, this.args);
      }
      eachChild(fn) {
          this.args.forEach(fn);
      }
      outputDefined() {
          return false;
      }
      static parse(args, context) {
          const op = args[0];
          const definition = CompoundExpression.definitions[op];
          if (!definition) {
              return context.error(`Unknown expression "${op}". If you wanted a literal array, use ["literal", [...]].`, 0);
          }
          // Now check argument types against each signature
          const type = Array.isArray(definition) ?
              definition[0] : definition.type;
          const availableOverloads = Array.isArray(definition) ?
              [[definition[1], definition[2]]] :
              definition.overloads;
          const overloads = availableOverloads.filter(([signature]) => (!Array.isArray(signature) || // varags
              signature.length === args.length - 1 // correct param count
          ));
          let signatureContext = null;
          for (const [params, evaluate] of overloads) {
              // Use a fresh context for each attempted signature so that, if
              // we eventually succeed, we haven't polluted `context.errors`.
              signatureContext = new ParsingContext(context.registry, isExpressionConstant, context.path, null, context.scope);
              // First parse all the args, potentially coercing to the
              // types expected by this overload.
              const parsedArgs = [];
              let argParseFailed = false;
              for (let i = 1; i < args.length; i++) {
                  const arg = args[i];
                  const expectedType = Array.isArray(params) ?
                      params[i - 1] :
                      params.type;
                  const parsed = signatureContext.parse(arg, 1 + parsedArgs.length, expectedType);
                  if (!parsed) {
                      argParseFailed = true;
                      break;
                  }
                  parsedArgs.push(parsed);
              }
              if (argParseFailed) {
                  // Couldn't coerce args of this overload to expected type, move
                  // on to next one.
                  continue;
              }
              if (Array.isArray(params)) {
                  if (params.length !== parsedArgs.length) {
                      signatureContext.error(`Expected ${params.length} arguments, but found ${parsedArgs.length} instead.`);
                      continue;
                  }
              }
              for (let i = 0; i < parsedArgs.length; i++) {
                  const expected = Array.isArray(params) ? params[i] : params.type;
                  const arg = parsedArgs[i];
                  signatureContext.concat(i + 1).checkSubtype(expected, arg.type);
              }
              if (signatureContext.errors.length === 0) {
                  return new CompoundExpression(op, type, evaluate, parsedArgs);
              }
          }
          if (overloads.length === 1) {
              context.errors.push(...signatureContext.errors);
          }
          else {
              const expected = overloads.length ? overloads : availableOverloads;
              const signatures = expected
                  .map(([params]) => stringifySignature(params))
                  .join(' | ');
              const actualTypes = [];
              // For error message, re-parse arguments without trying to
              // apply any coercions
              for (let i = 1; i < args.length; i++) {
                  const parsed = context.parse(args[i], 1 + actualTypes.length);
                  if (!parsed)
                      return null;
                  actualTypes.push(toString$1(parsed.type));
              }
              context.error(`Expected arguments of type ${signatures}, but found (${actualTypes.join(', ')}) instead.`);
          }
          return null;
      }
      static register(registry, definitions) {
          CompoundExpression.definitions = definitions;
          for (const name in definitions) {
              registry[name] = CompoundExpression;
          }
      }
  }
  function stringifySignature(signature) {
      if (Array.isArray(signature)) {
          return `(${signature.map(toString$1).join(', ')})`;
      }
      else {
          return `(${toString$1(signature.type)}...)`;
      }
  }
  function isExpressionConstant(expression) {
      if (expression instanceof Var) {
          return isExpressionConstant(expression.boundExpression);
      }
      else if (expression instanceof CompoundExpression && expression.name === 'error') {
          return false;
      }
      else if (expression instanceof CollatorExpression) {
          // Although the results of a Collator expression with fixed arguments
          // generally shouldn't change between executions, we can't serialize them
          // as constant expressions because results change based on environment.
          return false;
      }
      else if (expression instanceof Within) {
          return false;
      }
      const isTypeAnnotation = expression instanceof Coercion ||
          expression instanceof Assertion;
      let childrenConstant = true;
      expression.eachChild(child => {
          // We can _almost_ assume that if `expressions` children are constant,
          // they would already have been evaluated to Literal values when they
          // were parsed.  Type annotations are the exception, because they might
          // have been inferred and added after a child was parsed.
          // So we recurse into isConstant() for the children of type annotations,
          // but otherwise simply check whether they are Literals.
          if (isTypeAnnotation) {
              childrenConstant = childrenConstant && isExpressionConstant(child);
          }
          else {
              childrenConstant = childrenConstant && child instanceof Literal;
          }
      });
      if (!childrenConstant) {
          return false;
      }
      return isFeatureConstant(expression) &&
          isGlobalPropertyConstant(expression, ['zoom', 'heatmap-density', 'line-progress', 'accumulated', 'is-supported-script']);
  }
  function isFeatureConstant(e) {
      if (e instanceof CompoundExpression) {
          if (e.name === 'get' && e.args.length === 1) {
              return false;
          }
          else if (e.name === 'feature-state') {
              return false;
          }
          else if (e.name === 'has' && e.args.length === 1) {
              return false;
          }
          else if (e.name === 'properties' ||
              e.name === 'geometry-type' ||
              e.name === 'id') {
              return false;
          }
          else if (/^filter-/.test(e.name)) {
              return false;
          }
      }
      if (e instanceof Within) {
          return false;
      }
      let result = true;
      e.eachChild(arg => {
          if (result && !isFeatureConstant(arg)) {
              result = false;
          }
      });
      return result;
  }
  function isStateConstant(e) {
      if (e instanceof CompoundExpression) {
          if (e.name === 'feature-state') {
              return false;
          }
      }
      let result = true;
      e.eachChild(arg => {
          if (result && !isStateConstant(arg)) {
              result = false;
          }
      });
      return result;
  }
  function isGlobalPropertyConstant(e, properties) {
      if (e instanceof CompoundExpression && properties.indexOf(e.name) >= 0) {
          return false;
      }
      let result = true;
      e.eachChild((arg) => {
          if (result && !isGlobalPropertyConstant(arg, properties)) {
              result = false;
          }
      });
      return result;
  }

  /**
   * Returns the index of the last stop <= input, or 0 if it doesn't exist.
   * @private
   */
  function findStopLessThanOrEqualTo(stops, input) {
      const lastIndex = stops.length - 1;
      let lowerIndex = 0;
      let upperIndex = lastIndex;
      let currentIndex = 0;
      let currentValue, nextValue;
      while (lowerIndex <= upperIndex) {
          currentIndex = Math.floor((lowerIndex + upperIndex) / 2);
          currentValue = stops[currentIndex];
          nextValue = stops[currentIndex + 1];
          if (currentValue <= input) {
              if (currentIndex === lastIndex || input < nextValue) { // Search complete
                  return currentIndex;
              }
              lowerIndex = currentIndex + 1;
          }
          else if (currentValue > input) {
              upperIndex = currentIndex - 1;
          }
          else {
              throw new RuntimeError('Input is not a number.');
          }
      }
      return 0;
  }

  class Step {
      constructor(type, input, stops) {
          this.type = type;
          this.input = input;
          this.labels = [];
          this.outputs = [];
          for (const [label, expression] of stops) {
              this.labels.push(label);
              this.outputs.push(expression);
          }
      }
      static parse(args, context) {
          if (args.length - 1 < 4) {
              return context.error(`Expected at least 4 arguments, but found only ${args.length - 1}.`);
          }
          if ((args.length - 1) % 2 !== 0) {
              return context.error('Expected an even number of arguments.');
          }
          const input = context.parse(args[1], 1, NumberType);
          if (!input)
              return null;
          const stops = [];
          let outputType = null;
          if (context.expectedType && context.expectedType.kind !== 'value') {
              outputType = context.expectedType;
          }
          for (let i = 1; i < args.length; i += 2) {
              const label = i === 1 ? -Infinity : args[i];
              const value = args[i + 1];
              const labelKey = i;
              const valueKey = i + 1;
              if (typeof label !== 'number') {
                  return context.error('Input/output pairs for "step" expressions must be defined using literal numeric values (not computed expressions) for the input values.', labelKey);
              }
              if (stops.length && stops[stops.length - 1][0] >= label) {
                  return context.error('Input/output pairs for "step" expressions must be arranged with input values in strictly ascending order.', labelKey);
              }
              const parsed = context.parse(value, valueKey, outputType);
              if (!parsed)
                  return null;
              outputType = outputType || parsed.type;
              stops.push([label, parsed]);
          }
          return new Step(outputType, input, stops);
      }
      evaluate(ctx) {
          const labels = this.labels;
          const outputs = this.outputs;
          if (labels.length === 1) {
              return outputs[0].evaluate(ctx);
          }
          const value = this.input.evaluate(ctx);
          if (value <= labels[0]) {
              return outputs[0].evaluate(ctx);
          }
          const stopCount = labels.length;
          if (value >= labels[stopCount - 1]) {
              return outputs[stopCount - 1].evaluate(ctx);
          }
          const index = findStopLessThanOrEqualTo(labels, value);
          return outputs[index].evaluate(ctx);
      }
      eachChild(fn) {
          fn(this.input);
          for (const expression of this.outputs) {
              fn(expression);
          }
      }
      outputDefined() {
          return this.outputs.every(out => out.outputDefined());
      }
  }

  /**
   * Checks whether the specified color space is one of the supported interpolation color spaces.
   *
   * @param colorSpace Color space key to verify.
   * @returns `true` if the specified color space is one of the supported
   * interpolation color spaces, `false` otherwise
   */
  function isSupportedInterpolationColorSpace(colorSpace) {
      return colorSpace === 'rgb' || colorSpace === 'hcl' || colorSpace === 'lab';
  }
  /**
   * @param interpolationType Interpolation type
   * @returns interpolation fn
   * @deprecated use `interpolate[type]` instead
   */
  const interpolateFactory = (interpolationType) => {
      switch (interpolationType) {
          case 'number': return number;
          case 'color': return color;
          case 'array': return array;
          case 'padding': return padding;
          case 'variableAnchorOffsetCollection': return variableAnchorOffsetCollection;
      }
  };
  function number(from, to, t) {
      return from + t * (to - from);
  }
  function color(from, to, t, spaceKey = 'rgb') {
      switch (spaceKey) {
          case 'rgb': {
              const [r, g, b, alpha] = array(from.rgb, to.rgb, t);
              return new Color(r, g, b, alpha, false);
          }
          case 'hcl': {
              const [hue0, chroma0, light0, alphaF] = from.hcl;
              const [hue1, chroma1, light1, alphaT] = to.hcl;
              // https://github.com/gka/chroma.js/blob/cd1b3c0926c7a85cbdc3b1453b3a94006de91a92/src/interpolator/_hsx.js
              let hue, chroma;
              if (!isNaN(hue0) && !isNaN(hue1)) {
                  let dh = hue1 - hue0;
                  if (hue1 > hue0 && dh > 180) {
                      dh -= 360;
                  }
                  else if (hue1 < hue0 && hue0 - hue1 > 180) {
                      dh += 360;
                  }
                  hue = hue0 + t * dh;
              }
              else if (!isNaN(hue0)) {
                  hue = hue0;
                  if (light1 === 1 || light1 === 0)
                      chroma = chroma0;
              }
              else if (!isNaN(hue1)) {
                  hue = hue1;
                  if (light0 === 1 || light0 === 0)
                      chroma = chroma1;
              }
              else {
                  hue = NaN;
              }
              const [r, g, b, alpha] = hclToRgb([
                  hue,
                  chroma !== null && chroma !== void 0 ? chroma : number(chroma0, chroma1, t),
                  number(light0, light1, t),
                  number(alphaF, alphaT, t),
              ]);
              return new Color(r, g, b, alpha, false);
          }
          case 'lab': {
              const [r, g, b, alpha] = labToRgb(array(from.lab, to.lab, t));
              return new Color(r, g, b, alpha, false);
          }
      }
  }
  function array(from, to, t) {
      return from.map((d, i) => {
          return number(d, to[i], t);
      });
  }
  function padding(from, to, t) {
      return new Padding(array(from.values, to.values, t));
  }
  function variableAnchorOffsetCollection(from, to, t) {
      const fromValues = from.values;
      const toValues = to.values;
      if (fromValues.length !== toValues.length) {
          throw new RuntimeError(`Cannot interpolate values of different length. from: ${from.toString()}, to: ${to.toString()}`);
      }
      const output = [];
      for (let i = 0; i < fromValues.length; i += 2) {
          // Anchor entries must match
          if (fromValues[i] !== toValues[i]) {
              throw new RuntimeError(`Cannot interpolate values containing mismatched anchors. from[${i}]: ${fromValues[i]}, to[${i}]: ${toValues[i]}`);
          }
          output.push(fromValues[i]);
          // Interpolate the offset values for each anchor
          const [fx, fy] = fromValues[i + 1];
          const [tx, ty] = toValues[i + 1];
          output.push([number(fx, tx, t), number(fy, ty, t)]);
      }
      return new VariableAnchorOffsetCollection(output);
  }
  const interpolate = {
      number,
      color,
      array,
      padding,
      variableAnchorOffsetCollection
  };

  class Interpolate {
      constructor(type, operator, interpolation, input, stops) {
          this.type = type;
          this.operator = operator;
          this.interpolation = interpolation;
          this.input = input;
          this.labels = [];
          this.outputs = [];
          for (const [label, expression] of stops) {
              this.labels.push(label);
              this.outputs.push(expression);
          }
      }
      static interpolationFactor(interpolation, input, lower, upper) {
          let t = 0;
          if (interpolation.name === 'exponential') {
              t = exponentialInterpolation(input, interpolation.base, lower, upper);
          }
          else if (interpolation.name === 'linear') {
              t = exponentialInterpolation(input, 1, lower, upper);
          }
          else if (interpolation.name === 'cubic-bezier') {
              const c = interpolation.controlPoints;
              const ub = new UnitBezier(c[0], c[1], c[2], c[3]);
              t = ub.solve(exponentialInterpolation(input, 1, lower, upper));
          }
          return t;
      }
      static parse(args, context) {
          let [operator, interpolation, input, ...rest] = args;
          if (!Array.isArray(interpolation) || interpolation.length === 0) {
              return context.error('Expected an interpolation type expression.', 1);
          }
          if (interpolation[0] === 'linear') {
              interpolation = { name: 'linear' };
          }
          else if (interpolation[0] === 'exponential') {
              const base = interpolation[1];
              if (typeof base !== 'number')
                  return context.error('Exponential interpolation requires a numeric base.', 1, 1);
              interpolation = {
                  name: 'exponential',
                  base
              };
          }
          else if (interpolation[0] === 'cubic-bezier') {
              const controlPoints = interpolation.slice(1);
              if (controlPoints.length !== 4 ||
                  controlPoints.some(t => typeof t !== 'number' || t < 0 || t > 1)) {
                  return context.error('Cubic bezier interpolation requires four numeric arguments with values between 0 and 1.', 1);
              }
              interpolation = {
                  name: 'cubic-bezier',
                  controlPoints: controlPoints
              };
          }
          else {
              return context.error(`Unknown interpolation type ${String(interpolation[0])}`, 1, 0);
          }
          if (args.length - 1 < 4) {
              return context.error(`Expected at least 4 arguments, but found only ${args.length - 1}.`);
          }
          if ((args.length - 1) % 2 !== 0) {
              return context.error('Expected an even number of arguments.');
          }
          input = context.parse(input, 2, NumberType);
          if (!input)
              return null;
          const stops = [];
          let outputType = null;
          if (operator === 'interpolate-hcl' || operator === 'interpolate-lab') {
              outputType = ColorType;
          }
          else if (context.expectedType && context.expectedType.kind !== 'value') {
              outputType = context.expectedType;
          }
          for (let i = 0; i < rest.length; i += 2) {
              const label = rest[i];
              const value = rest[i + 1];
              const labelKey = i + 3;
              const valueKey = i + 4;
              if (typeof label !== 'number') {
                  return context.error('Input/output pairs for "interpolate" expressions must be defined using literal numeric values (not computed expressions) for the input values.', labelKey);
              }
              if (stops.length && stops[stops.length - 1][0] >= label) {
                  return context.error('Input/output pairs for "interpolate" expressions must be arranged with input values in strictly ascending order.', labelKey);
              }
              const parsed = context.parse(value, valueKey, outputType);
              if (!parsed)
                  return null;
              outputType = outputType || parsed.type;
              stops.push([label, parsed]);
          }
          if (!verifyType(outputType, NumberType) &&
              !verifyType(outputType, ColorType) &&
              !verifyType(outputType, PaddingType) &&
              !verifyType(outputType, VariableAnchorOffsetCollectionType) &&
              !verifyType(outputType, array$1(NumberType))) {
              return context.error(`Type ${toString$1(outputType)} is not interpolatable.`);
          }
          return new Interpolate(outputType, operator, interpolation, input, stops);
      }
      evaluate(ctx) {
          const labels = this.labels;
          const outputs = this.outputs;
          if (labels.length === 1) {
              return outputs[0].evaluate(ctx);
          }
          const value = this.input.evaluate(ctx);
          if (value <= labels[0]) {
              return outputs[0].evaluate(ctx);
          }
          const stopCount = labels.length;
          if (value >= labels[stopCount - 1]) {
              return outputs[stopCount - 1].evaluate(ctx);
          }
          const index = findStopLessThanOrEqualTo(labels, value);
          const lower = labels[index];
          const upper = labels[index + 1];
          const t = Interpolate.interpolationFactor(this.interpolation, value, lower, upper);
          const outputLower = outputs[index].evaluate(ctx);
          const outputUpper = outputs[index + 1].evaluate(ctx);
          switch (this.operator) {
              case 'interpolate':
                  return interpolate[this.type.kind](outputLower, outputUpper, t);
              case 'interpolate-hcl':
                  return interpolate.color(outputLower, outputUpper, t, 'hcl');
              case 'interpolate-lab':
                  return interpolate.color(outputLower, outputUpper, t, 'lab');
          }
      }
      eachChild(fn) {
          fn(this.input);
          for (const expression of this.outputs) {
              fn(expression);
          }
      }
      outputDefined() {
          return this.outputs.every(out => out.outputDefined());
      }
  }
  /**
   * Returns a ratio that can be used to interpolate between exponential function
   * stops.
   * How it works: Two consecutive stop values define a (scaled and shifted) exponential function `f(x) = a * base^x + b`, where `base` is the user-specified base,
   * and `a` and `b` are constants affording sufficient degrees of freedom to fit
   * the function to the given stops.
   *
   * Here's a bit of algebra that lets us compute `f(x)` directly from the stop
   * values without explicitly solving for `a` and `b`:
   *
   * First stop value: `f(x0) = y0 = a * base^x0 + b`
   * Second stop value: `f(x1) = y1 = a * base^x1 + b`
   * => `y1 - y0 = a(base^x1 - base^x0)`
   * => `a = (y1 - y0)/(base^x1 - base^x0)`
   *
   * Desired value: `f(x) = y = a * base^x + b`
   * => `f(x) = y0 + a * (base^x - base^x0)`
   *
   * From the above, we can replace the `a` in `a * (base^x - base^x0)` and do a
   * little algebra:
   * ```
   * a * (base^x - base^x0) = (y1 - y0)/(base^x1 - base^x0) * (base^x - base^x0)
   *                     = (y1 - y0) * (base^x - base^x0) / (base^x1 - base^x0)
   * ```
   *
   * If we let `(base^x - base^x0) / (base^x1 base^x0)`, then we have
   * `f(x) = y0 + (y1 - y0) * ratio`.  In other words, `ratio` may be treated as
   * an interpolation factor between the two stops' output values.
   *
   * (Note: a slightly different form for `ratio`,
   * `(base^(x-x0) - 1) / (base^(x1-x0) - 1) `, is equivalent, but requires fewer
   * expensive `Math.pow()` operations.)
   *
   * @private
  */
  function exponentialInterpolation(input, base, lowerValue, upperValue) {
      const difference = upperValue - lowerValue;
      const progress = input - lowerValue;
      if (difference === 0) {
          return 0;
      }
      else if (base === 1) {
          return progress / difference;
      }
      else {
          return (Math.pow(base, progress) - 1) / (Math.pow(base, difference) - 1);
      }
  }

  class Coalesce {
      constructor(type, args) {
          this.type = type;
          this.args = args;
      }
      static parse(args, context) {
          if (args.length < 2) {
              return context.error('Expectected at least one argument.');
          }
          let outputType = null;
          const expectedType = context.expectedType;
          if (expectedType && expectedType.kind !== 'value') {
              outputType = expectedType;
          }
          const parsedArgs = [];
          for (const arg of args.slice(1)) {
              const parsed = context.parse(arg, 1 + parsedArgs.length, outputType, undefined, { typeAnnotation: 'omit' });
              if (!parsed)
                  return null;
              outputType = outputType || parsed.type;
              parsedArgs.push(parsed);
          }
          if (!outputType)
              throw new Error('No output type');
          // Above, we parse arguments without inferred type annotation so that
          // they don't produce a runtime error for `null` input, which would
          // preempt the desired null-coalescing behavior.
          // Thus, if any of our arguments would have needed an annotation, we
          // need to wrap the enclosing coalesce expression with it instead.
          const needsAnnotation = expectedType &&
              parsedArgs.some(arg => checkSubtype(expectedType, arg.type));
          return needsAnnotation ?
              new Coalesce(ValueType, parsedArgs) :
              new Coalesce(outputType, parsedArgs);
      }
      evaluate(ctx) {
          let result = null;
          let argCount = 0;
          let requestedImageName;
          for (const arg of this.args) {
              argCount++;
              result = arg.evaluate(ctx);
              // we need to keep track of the first requested image in a coalesce statement
              // if coalesce can't find a valid image, we return the first image name so styleimagemissing can fire
              if (result && result instanceof ResolvedImage && !result.available) {
                  if (!requestedImageName) {
                      requestedImageName = result.name;
                  }
                  result = null;
                  if (argCount === this.args.length) {
                      result = requestedImageName;
                  }
              }
              if (result !== null)
                  break;
          }
          return result;
      }
      eachChild(fn) {
          this.args.forEach(fn);
      }
      outputDefined() {
          return this.args.every(arg => arg.outputDefined());
      }
  }

  class Let {
      constructor(bindings, result) {
          this.type = result.type;
          this.bindings = [].concat(bindings);
          this.result = result;
      }
      evaluate(ctx) {
          return this.result.evaluate(ctx);
      }
      eachChild(fn) {
          for (const binding of this.bindings) {
              fn(binding[1]);
          }
          fn(this.result);
      }
      static parse(args, context) {
          if (args.length < 4)
              return context.error(`Expected at least 3 arguments, but found ${args.length - 1} instead.`);
          const bindings = [];
          for (let i = 1; i < args.length - 1; i += 2) {
              const name = args[i];
              if (typeof name !== 'string') {
                  return context.error(`Expected string, but found ${typeof name} instead.`, i);
              }
              if (/[^a-zA-Z0-9_]/.test(name)) {
                  return context.error('Variable names must contain only alphanumeric characters or \'_\'.', i);
              }
              const value = context.parse(args[i + 1], i + 1);
              if (!value)
                  return null;
              bindings.push([name, value]);
          }
          const result = context.parse(args[args.length - 1], args.length - 1, context.expectedType, bindings);
          if (!result)
              return null;
          return new Let(bindings, result);
      }
      outputDefined() {
          return this.result.outputDefined();
      }
  }

  class At {
      constructor(type, index, input) {
          this.type = type;
          this.index = index;
          this.input = input;
      }
      static parse(args, context) {
          if (args.length !== 3)
              return context.error(`Expected 2 arguments, but found ${args.length - 1} instead.`);
          const index = context.parse(args[1], 1, NumberType);
          const input = context.parse(args[2], 2, array$1(context.expectedType || ValueType));
          if (!index || !input)
              return null;
          const t = input.type;
          return new At(t.itemType, index, input);
      }
      evaluate(ctx) {
          const index = this.index.evaluate(ctx);
          const array = this.input.evaluate(ctx);
          if (index < 0) {
              throw new RuntimeError(`Array index out of bounds: ${index} < 0.`);
          }
          if (index >= array.length) {
              throw new RuntimeError(`Array index out of bounds: ${index} > ${array.length - 1}.`);
          }
          if (index !== Math.floor(index)) {
              throw new RuntimeError(`Array index must be an integer, but found ${index} instead.`);
          }
          return array[index];
      }
      eachChild(fn) {
          fn(this.index);
          fn(this.input);
      }
      outputDefined() {
          return false;
      }
  }

  class In {
      constructor(needle, haystack) {
          this.type = BooleanType;
          this.needle = needle;
          this.haystack = haystack;
      }
      static parse(args, context) {
          if (args.length !== 3) {
              return context.error(`Expected 2 arguments, but found ${args.length - 1} instead.`);
          }
          const needle = context.parse(args[1], 1, ValueType);
          const haystack = context.parse(args[2], 2, ValueType);
          if (!needle || !haystack)
              return null;
          if (!isValidType(needle.type, [BooleanType, StringType, NumberType, NullType, ValueType])) {
              return context.error(`Expected first argument to be of type boolean, string, number or null, but found ${toString$1(needle.type)} instead`);
          }
          return new In(needle, haystack);
      }
      evaluate(ctx) {
          const needle = this.needle.evaluate(ctx);
          const haystack = this.haystack.evaluate(ctx);
          if (!haystack)
              return false;
          if (!isValidNativeType(needle, ['boolean', 'string', 'number', 'null'])) {
              throw new RuntimeError(`Expected first argument to be of type boolean, string, number or null, but found ${toString$1(typeOf(needle))} instead.`);
          }
          if (!isValidNativeType(haystack, ['string', 'array'])) {
              throw new RuntimeError(`Expected second argument to be of type array or string, but found ${toString$1(typeOf(haystack))} instead.`);
          }
          return haystack.indexOf(needle) >= 0;
      }
      eachChild(fn) {
          fn(this.needle);
          fn(this.haystack);
      }
      outputDefined() {
          return true;
      }
  }

  class IndexOf {
      constructor(needle, haystack, fromIndex) {
          this.type = NumberType;
          this.needle = needle;
          this.haystack = haystack;
          this.fromIndex = fromIndex;
      }
      static parse(args, context) {
          if (args.length <= 2 || args.length >= 5) {
              return context.error(`Expected 3 or 4 arguments, but found ${args.length - 1} instead.`);
          }
          const needle = context.parse(args[1], 1, ValueType);
          const haystack = context.parse(args[2], 2, ValueType);
          if (!needle || !haystack)
              return null;
          if (!isValidType(needle.type, [BooleanType, StringType, NumberType, NullType, ValueType])) {
              return context.error(`Expected first argument to be of type boolean, string, number or null, but found ${toString$1(needle.type)} instead`);
          }
          if (args.length === 4) {
              const fromIndex = context.parse(args[3], 3, NumberType);
              if (!fromIndex)
                  return null;
              return new IndexOf(needle, haystack, fromIndex);
          }
          else {
              return new IndexOf(needle, haystack);
          }
      }
      evaluate(ctx) {
          const needle = this.needle.evaluate(ctx);
          const haystack = this.haystack.evaluate(ctx);
          if (!isValidNativeType(needle, ['boolean', 'string', 'number', 'null'])) {
              throw new RuntimeError(`Expected first argument to be of type boolean, string, number or null, but found ${toString$1(typeOf(needle))} instead.`);
          }
          if (!isValidNativeType(haystack, ['string', 'array'])) {
              throw new RuntimeError(`Expected second argument to be of type array or string, but found ${toString$1(typeOf(haystack))} instead.`);
          }
          if (this.fromIndex) {
              const fromIndex = this.fromIndex.evaluate(ctx);
              return haystack.indexOf(needle, fromIndex);
          }
          return haystack.indexOf(needle);
      }
      eachChild(fn) {
          fn(this.needle);
          fn(this.haystack);
          if (this.fromIndex) {
              fn(this.fromIndex);
          }
      }
      outputDefined() {
          return false;
      }
  }

  class Match {
      constructor(inputType, outputType, input, cases, outputs, otherwise) {
          this.inputType = inputType;
          this.type = outputType;
          this.input = input;
          this.cases = cases;
          this.outputs = outputs;
          this.otherwise = otherwise;
      }
      static parse(args, context) {
          if (args.length < 5)
              return context.error(`Expected at least 4 arguments, but found only ${args.length - 1}.`);
          if (args.length % 2 !== 1)
              return context.error('Expected an even number of arguments.');
          let inputType;
          let outputType;
          if (context.expectedType && context.expectedType.kind !== 'value') {
              outputType = context.expectedType;
          }
          const cases = {};
          const outputs = [];
          for (let i = 2; i < args.length - 1; i += 2) {
              let labels = args[i];
              const value = args[i + 1];
              if (!Array.isArray(labels)) {
                  labels = [labels];
              }
              const labelContext = context.concat(i);
              if (labels.length === 0) {
                  return labelContext.error('Expected at least one branch label.');
              }
              for (const label of labels) {
                  if (typeof label !== 'number' && typeof label !== 'string') {
                      return labelContext.error('Branch labels must be numbers or strings.');
                  }
                  else if (typeof label === 'number' && Math.abs(label) > Number.MAX_SAFE_INTEGER) {
                      return labelContext.error(`Branch labels must be integers no larger than ${Number.MAX_SAFE_INTEGER}.`);
                  }
                  else if (typeof label === 'number' && Math.floor(label) !== label) {
                      return labelContext.error('Numeric branch labels must be integer values.');
                  }
                  else if (!inputType) {
                      inputType = typeOf(label);
                  }
                  else if (labelContext.checkSubtype(inputType, typeOf(label))) {
                      return null;
                  }
                  if (typeof cases[String(label)] !== 'undefined') {
                      return labelContext.error('Branch labels must be unique.');
                  }
                  cases[String(label)] = outputs.length;
              }
              const result = context.parse(value, i, outputType);
              if (!result)
                  return null;
              outputType = outputType || result.type;
              outputs.push(result);
          }
          const input = context.parse(args[1], 1, ValueType);
          if (!input)
              return null;
          const otherwise = context.parse(args[args.length - 1], args.length - 1, outputType);
          if (!otherwise)
              return null;
          if (input.type.kind !== 'value' && context.concat(1).checkSubtype(inputType, input.type)) {
              return null;
          }
          return new Match(inputType, outputType, input, cases, outputs, otherwise);
      }
      evaluate(ctx) {
          const input = this.input.evaluate(ctx);
          const output = (typeOf(input) === this.inputType && this.outputs[this.cases[input]]) || this.otherwise;
          return output.evaluate(ctx);
      }
      eachChild(fn) {
          fn(this.input);
          this.outputs.forEach(fn);
          fn(this.otherwise);
      }
      outputDefined() {
          return this.outputs.every(out => out.outputDefined()) && this.otherwise.outputDefined();
      }
  }

  class Case {
      constructor(type, branches, otherwise) {
          this.type = type;
          this.branches = branches;
          this.otherwise = otherwise;
      }
      static parse(args, context) {
          if (args.length < 4)
              return context.error(`Expected at least 3 arguments, but found only ${args.length - 1}.`);
          if (args.length % 2 !== 0)
              return context.error('Expected an odd number of arguments.');
          let outputType;
          if (context.expectedType && context.expectedType.kind !== 'value') {
              outputType = context.expectedType;
          }
          const branches = [];
          for (let i = 1; i < args.length - 1; i += 2) {
              const test = context.parse(args[i], i, BooleanType);
              if (!test)
                  return null;
              const result = context.parse(args[i + 1], i + 1, outputType);
              if (!result)
                  return null;
              branches.push([test, result]);
              outputType = outputType || result.type;
          }
          const otherwise = context.parse(args[args.length - 1], args.length - 1, outputType);
          if (!otherwise)
              return null;
          if (!outputType)
              throw new Error('Can\'t infer output type');
          return new Case(outputType, branches, otherwise);
      }
      evaluate(ctx) {
          for (const [test, expression] of this.branches) {
              if (test.evaluate(ctx)) {
                  return expression.evaluate(ctx);
              }
          }
          return this.otherwise.evaluate(ctx);
      }
      eachChild(fn) {
          for (const [test, expression] of this.branches) {
              fn(test);
              fn(expression);
          }
          fn(this.otherwise);
      }
      outputDefined() {
          return this.branches.every(([_, out]) => out.outputDefined()) && this.otherwise.outputDefined();
      }
  }

  class Slice {
      constructor(type, input, beginIndex, endIndex) {
          this.type = type;
          this.input = input;
          this.beginIndex = beginIndex;
          this.endIndex = endIndex;
      }
      static parse(args, context) {
          if (args.length <= 2 || args.length >= 5) {
              return context.error(`Expected 3 or 4 arguments, but found ${args.length - 1} instead.`);
          }
          const input = context.parse(args[1], 1, ValueType);
          const beginIndex = context.parse(args[2], 2, NumberType);
          if (!input || !beginIndex)
              return null;
          if (!isValidType(input.type, [array$1(ValueType), StringType, ValueType])) {
              return context.error(`Expected first argument to be of type array or string, but found ${toString$1(input.type)} instead`);
          }
          if (args.length === 4) {
              const endIndex = context.parse(args[3], 3, NumberType);
              if (!endIndex)
                  return null;
              return new Slice(input.type, input, beginIndex, endIndex);
          }
          else {
              return new Slice(input.type, input, beginIndex);
          }
      }
      evaluate(ctx) {
          const input = this.input.evaluate(ctx);
          const beginIndex = this.beginIndex.evaluate(ctx);
          if (!isValidNativeType(input, ['string', 'array'])) {
              throw new RuntimeError(`Expected first argument to be of type array or string, but found ${toString$1(typeOf(input))} instead.`);
          }
          if (this.endIndex) {
              const endIndex = this.endIndex.evaluate(ctx);
              return input.slice(beginIndex, endIndex);
          }
          return input.slice(beginIndex);
      }
      eachChild(fn) {
          fn(this.input);
          fn(this.beginIndex);
          if (this.endIndex) {
              fn(this.endIndex);
          }
      }
      outputDefined() {
          return false;
      }
  }

  function isComparableType(op, type) {
      if (op === '==' || op === '!=') {
          // equality operator
          return type.kind === 'boolean' ||
              type.kind === 'string' ||
              type.kind === 'number' ||
              type.kind === 'null' ||
              type.kind === 'value';
      }
      else {
          // ordering operator
          return type.kind === 'string' ||
              type.kind === 'number' ||
              type.kind === 'value';
      }
  }
  function eq(ctx, a, b) { return a === b; }
  function neq(ctx, a, b) { return a !== b; }
  function lt(ctx, a, b) { return a < b; }
  function gt(ctx, a, b) { return a > b; }
  function lteq(ctx, a, b) { return a <= b; }
  function gteq(ctx, a, b) { return a >= b; }
  function eqCollate(ctx, a, b, c) { return c.compare(a, b) === 0; }
  function neqCollate(ctx, a, b, c) { return !eqCollate(ctx, a, b, c); }
  function ltCollate(ctx, a, b, c) { return c.compare(a, b) < 0; }
  function gtCollate(ctx, a, b, c) { return c.compare(a, b) > 0; }
  function lteqCollate(ctx, a, b, c) { return c.compare(a, b) <= 0; }
  function gteqCollate(ctx, a, b, c) { return c.compare(a, b) >= 0; }
  /**
   * Special form for comparison operators, implementing the signatures:
   * - (T, T, ?Collator) => boolean
   * - (T, value, ?Collator) => boolean
   * - (value, T, ?Collator) => boolean
   *
   * For inequalities, T must be either value, string, or number. For ==/!=, it
   * can also be boolean or null.
   *
   * Equality semantics are equivalent to Javascript's strict equality (===/!==)
   * -- i.e., when the arguments' types don't match, == evaluates to false, != to
   * true.
   *
   * When types don't match in an ordering comparison, a runtime error is thrown.
   *
   * @private
   */
  function makeComparison(op, compareBasic, compareWithCollator) {
      const isOrderComparison = op !== '==' && op !== '!=';
      return class Comparison {
          constructor(lhs, rhs, collator) {
              this.type = BooleanType;
              this.lhs = lhs;
              this.rhs = rhs;
              this.collator = collator;
              this.hasUntypedArgument = lhs.type.kind === 'value' || rhs.type.kind === 'value';
          }
          static parse(args, context) {
              if (args.length !== 3 && args.length !== 4)
                  return context.error('Expected two or three arguments.');
              const op = args[0];
              let lhs = context.parse(args[1], 1, ValueType);
              if (!lhs)
                  return null;
              if (!isComparableType(op, lhs.type)) {
                  return context.concat(1).error(`"${op}" comparisons are not supported for type '${toString$1(lhs.type)}'.`);
              }
              let rhs = context.parse(args[2], 2, ValueType);
              if (!rhs)
                  return null;
              if (!isComparableType(op, rhs.type)) {
                  return context.concat(2).error(`"${op}" comparisons are not supported for type '${toString$1(rhs.type)}'.`);
              }
              if (lhs.type.kind !== rhs.type.kind &&
                  lhs.type.kind !== 'value' &&
                  rhs.type.kind !== 'value') {
                  return context.error(`Cannot compare types '${toString$1(lhs.type)}' and '${toString$1(rhs.type)}'.`);
              }
              if (isOrderComparison) {
                  // typing rules specific to less/greater than operators
                  if (lhs.type.kind === 'value' && rhs.type.kind !== 'value') {
                      // (value, T)
                      lhs = new Assertion(rhs.type, [lhs]);
                  }
                  else if (lhs.type.kind !== 'value' && rhs.type.kind === 'value') {
                      // (T, value)
                      rhs = new Assertion(lhs.type, [rhs]);
                  }
              }
              let collator = null;
              if (args.length === 4) {
                  if (lhs.type.kind !== 'string' &&
                      rhs.type.kind !== 'string' &&
                      lhs.type.kind !== 'value' &&
                      rhs.type.kind !== 'value') {
                      return context.error('Cannot use collator to compare non-string types.');
                  }
                  collator = context.parse(args[3], 3, CollatorType);
                  if (!collator)
                      return null;
              }
              return new Comparison(lhs, rhs, collator);
          }
          evaluate(ctx) {
              const lhs = this.lhs.evaluate(ctx);
              const rhs = this.rhs.evaluate(ctx);
              if (isOrderComparison && this.hasUntypedArgument) {
                  const lt = typeOf(lhs);
                  const rt = typeOf(rhs);
                  // check that type is string or number, and equal
                  if (lt.kind !== rt.kind || !(lt.kind === 'string' || lt.kind === 'number')) {
                      throw new RuntimeError(`Expected arguments for "${op}" to be (string, string) or (number, number), but found (${lt.kind}, ${rt.kind}) instead.`);
                  }
              }
              if (this.collator && !isOrderComparison && this.hasUntypedArgument) {
                  const lt = typeOf(lhs);
                  const rt = typeOf(rhs);
                  if (lt.kind !== 'string' || rt.kind !== 'string') {
                      return compareBasic(ctx, lhs, rhs);
                  }
              }
              return this.collator ?
                  compareWithCollator(ctx, lhs, rhs, this.collator.evaluate(ctx)) :
                  compareBasic(ctx, lhs, rhs);
          }
          eachChild(fn) {
              fn(this.lhs);
              fn(this.rhs);
              if (this.collator) {
                  fn(this.collator);
              }
          }
          outputDefined() {
              return true;
          }
      };
  }
  const Equals = makeComparison('==', eq, eqCollate);
  const NotEquals = makeComparison('!=', neq, neqCollate);
  const LessThan = makeComparison('<', lt, ltCollate);
  const GreaterThan = makeComparison('>', gt, gtCollate);
  const LessThanOrEqual = makeComparison('<=', lteq, lteqCollate);
  const GreaterThanOrEqual = makeComparison('>=', gteq, gteqCollate);

  class NumberFormat {
      constructor(number, locale, currency, minFractionDigits, maxFractionDigits) {
          this.type = StringType;
          this.number = number;
          this.locale = locale;
          this.currency = currency;
          this.minFractionDigits = minFractionDigits;
          this.maxFractionDigits = maxFractionDigits;
      }
      static parse(args, context) {
          if (args.length !== 3)
              return context.error('Expected two arguments.');
          const number = context.parse(args[1], 1, NumberType);
          if (!number)
              return null;
          const options = args[2];
          if (typeof options !== 'object' || Array.isArray(options))
              return context.error('NumberFormat options argument must be an object.');
          let locale = null;
          if (options['locale']) {
              locale = context.parse(options['locale'], 1, StringType);
              if (!locale)
                  return null;
          }
          let currency = null;
          if (options['currency']) {
              currency = context.parse(options['currency'], 1, StringType);
              if (!currency)
                  return null;
          }
          let minFractionDigits = null;
          if (options['min-fraction-digits']) {
              minFractionDigits = context.parse(options['min-fraction-digits'], 1, NumberType);
              if (!minFractionDigits)
                  return null;
          }
          let maxFractionDigits = null;
          if (options['max-fraction-digits']) {
              maxFractionDigits = context.parse(options['max-fraction-digits'], 1, NumberType);
              if (!maxFractionDigits)
                  return null;
          }
          return new NumberFormat(number, locale, currency, minFractionDigits, maxFractionDigits);
      }
      evaluate(ctx) {
          return new Intl.NumberFormat(this.locale ? this.locale.evaluate(ctx) : [], {
              style: this.currency ? 'currency' : 'decimal',
              currency: this.currency ? this.currency.evaluate(ctx) : undefined,
              minimumFractionDigits: this.minFractionDigits ? this.minFractionDigits.evaluate(ctx) : undefined,
              maximumFractionDigits: this.maxFractionDigits ? this.maxFractionDigits.evaluate(ctx) : undefined,
          }).format(this.number.evaluate(ctx));
      }
      eachChild(fn) {
          fn(this.number);
          if (this.locale) {
              fn(this.locale);
          }
          if (this.currency) {
              fn(this.currency);
          }
          if (this.minFractionDigits) {
              fn(this.minFractionDigits);
          }
          if (this.maxFractionDigits) {
              fn(this.maxFractionDigits);
          }
      }
      outputDefined() {
          return false;
      }
  }

  class FormatExpression {
      constructor(sections) {
          this.type = FormattedType;
          this.sections = sections;
      }
      static parse(args, context) {
          if (args.length < 2) {
              return context.error('Expected at least one argument.');
          }
          const firstArg = args[1];
          if (!Array.isArray(firstArg) && typeof firstArg === 'object') {
              return context.error('First argument must be an image or text section.');
          }
          const sections = [];
          let nextTokenMayBeObject = false;
          for (let i = 1; i <= args.length - 1; ++i) {
              const arg = args[i];
              if (nextTokenMayBeObject && typeof arg === 'object' && !Array.isArray(arg)) {
                  nextTokenMayBeObject = false;
                  let scale = null;
                  if (arg['font-scale']) {
                      scale = context.parse(arg['font-scale'], 1, NumberType);
                      if (!scale)
                          return null;
                  }
                  let font = null;
                  if (arg['text-font']) {
                      font = context.parse(arg['text-font'], 1, array$1(StringType));
                      if (!font)
                          return null;
                  }
                  let textColor = null;
                  if (arg['text-color']) {
                      textColor = context.parse(arg['text-color'], 1, ColorType);
                      if (!textColor)
                          return null;
                  }
                  const lastExpression = sections[sections.length - 1];
                  lastExpression.scale = scale;
                  lastExpression.font = font;
                  lastExpression.textColor = textColor;
              }
              else {
                  const content = context.parse(args[i], 1, ValueType);
                  if (!content)
                      return null;
                  const kind = content.type.kind;
                  if (kind !== 'string' && kind !== 'value' && kind !== 'null' && kind !== 'resolvedImage')
                      return context.error('Formatted text type must be \'string\', \'value\', \'image\' or \'null\'.');
                  nextTokenMayBeObject = true;
                  sections.push({ content, scale: null, font: null, textColor: null });
              }
          }
          return new FormatExpression(sections);
      }
      evaluate(ctx) {
          const evaluateSection = section => {
              const evaluatedContent = section.content.evaluate(ctx);
              if (typeOf(evaluatedContent) === ResolvedImageType) {
                  return new FormattedSection('', evaluatedContent, null, null, null);
              }
              return new FormattedSection(toString(evaluatedContent), null, section.scale ? section.scale.evaluate(ctx) : null, section.font ? section.font.evaluate(ctx).join(',') : null, section.textColor ? section.textColor.evaluate(ctx) : null);
          };
          return new Formatted(this.sections.map(evaluateSection));
      }
      eachChild(fn) {
          for (const section of this.sections) {
              fn(section.content);
              if (section.scale) {
                  fn(section.scale);
              }
              if (section.font) {
                  fn(section.font);
              }
              if (section.textColor) {
                  fn(section.textColor);
              }
          }
      }
      outputDefined() {
          // Technically the combinatoric set of all children
          // Usually, this.text will be undefined anyway
          return false;
      }
  }

  class ImageExpression {
      constructor(input) {
          this.type = ResolvedImageType;
          this.input = input;
      }
      static parse(args, context) {
          if (args.length !== 2) {
              return context.error('Expected two arguments.');
          }
          const name = context.parse(args[1], 1, StringType);
          if (!name)
              return context.error('No image name provided.');
          return new ImageExpression(name);
      }
      evaluate(ctx) {
          const evaluatedImageName = this.input.evaluate(ctx);
          const value = ResolvedImage.fromString(evaluatedImageName);
          if (value && ctx.availableImages)
              value.available = ctx.availableImages.indexOf(evaluatedImageName) > -1;
          return value;
      }
      eachChild(fn) {
          fn(this.input);
      }
      outputDefined() {
          // The output of image is determined by the list of available images in the evaluation context
          return false;
      }
  }

  class Length {
      constructor(input) {
          this.type = NumberType;
          this.input = input;
      }
      static parse(args, context) {
          if (args.length !== 2)
              return context.error(`Expected 1 argument, but found ${args.length - 1} instead.`);
          const input = context.parse(args[1], 1);
          if (!input)
              return null;
          if (input.type.kind !== 'array' && input.type.kind !== 'string' && input.type.kind !== 'value')
              return context.error(`Expected argument of type string or array, but found ${toString$1(input.type)} instead.`);
          return new Length(input);
      }
      evaluate(ctx) {
          const input = this.input.evaluate(ctx);
          if (typeof input === 'string') {
              return input.length;
          }
          else if (Array.isArray(input)) {
              return input.length;
          }
          else {
              throw new RuntimeError(`Expected value to be of type string or array, but found ${toString$1(typeOf(input))} instead.`);
          }
      }
      eachChild(fn) {
          fn(this.input);
      }
      outputDefined() {
          return false;
      }
  }

  const expressions = {
      // special forms
      '==': Equals,
      '!=': NotEquals,
      '>': GreaterThan,
      '<': LessThan,
      '>=': GreaterThanOrEqual,
      '<=': LessThanOrEqual,
      'array': Assertion,
      'at': At,
      'boolean': Assertion,
      'case': Case,
      'coalesce': Coalesce,
      'collator': CollatorExpression,
      'format': FormatExpression,
      'image': ImageExpression,
      'in': In,
      'index-of': IndexOf,
      'interpolate': Interpolate,
      'interpolate-hcl': Interpolate,
      'interpolate-lab': Interpolate,
      'length': Length,
      'let': Let,
      'literal': Literal,
      'match': Match,
      'number': Assertion,
      'number-format': NumberFormat,
      'object': Assertion,
      'slice': Slice,
      'step': Step,
      'string': Assertion,
      'to-boolean': Coercion,
      'to-color': Coercion,
      'to-number': Coercion,
      'to-string': Coercion,
      'var': Var,
      'within': Within
  };
  function rgba(ctx, [r, g, b, a]) {
      r = r.evaluate(ctx);
      g = g.evaluate(ctx);
      b = b.evaluate(ctx);
      const alpha = a ? a.evaluate(ctx) : 1;
      const error = validateRGBA(r, g, b, alpha);
      if (error)
          throw new RuntimeError(error);
      return new Color(r / 255, g / 255, b / 255, alpha, false);
  }
  function has(key, obj) {
      return key in obj;
  }
  function get(key, obj) {
      const v = obj[key];
      return typeof v === 'undefined' ? null : v;
  }
  function binarySearch(v, a, i, j) {
      while (i <= j) {
          const m = (i + j) >> 1;
          if (a[m] === v)
              return true;
          if (a[m] > v)
              j = m - 1;
          else
              i = m + 1;
      }
      return false;
  }
  function varargs(type) {
      return { type };
  }
  CompoundExpression.register(expressions, {
      'error': [
          ErrorType,
          [StringType],
          (ctx, [v]) => { throw new RuntimeError(v.evaluate(ctx)); }
      ],
      'typeof': [
          StringType,
          [ValueType],
          (ctx, [v]) => toString$1(typeOf(v.evaluate(ctx)))
      ],
      'to-rgba': [
          array$1(NumberType, 4),
          [ColorType],
          (ctx, [v]) => {
              const [r, g, b, a] = v.evaluate(ctx).rgb;
              return [r * 255, g * 255, b * 255, a];
          },
      ],
      'rgb': [
          ColorType,
          [NumberType, NumberType, NumberType],
          rgba
      ],
      'rgba': [
          ColorType,
          [NumberType, NumberType, NumberType, NumberType],
          rgba
      ],
      'has': {
          type: BooleanType,
          overloads: [
              [
                  [StringType],
                  (ctx, [key]) => has(key.evaluate(ctx), ctx.properties())
              ], [
                  [StringType, ObjectType],
                  (ctx, [key, obj]) => has(key.evaluate(ctx), obj.evaluate(ctx))
              ]
          ]
      },
      'get': {
          type: ValueType,
          overloads: [
              [
                  [StringType],
                  (ctx, [key]) => get(key.evaluate(ctx), ctx.properties())
              ], [
                  [StringType, ObjectType],
                  (ctx, [key, obj]) => get(key.evaluate(ctx), obj.evaluate(ctx))
              ]
          ]
      },
      'feature-state': [
          ValueType,
          [StringType],
          (ctx, [key]) => get(key.evaluate(ctx), ctx.featureState || {})
      ],
      'properties': [
          ObjectType,
          [],
          (ctx) => ctx.properties()
      ],
      'geometry-type': [
          StringType,
          [],
          (ctx) => ctx.geometryType()
      ],
      'id': [
          ValueType,
          [],
          (ctx) => ctx.id()
      ],
      'zoom': [
          NumberType,
          [],
          (ctx) => ctx.globals.zoom
      ],
      'heatmap-density': [
          NumberType,
          [],
          (ctx) => ctx.globals.heatmapDensity || 0
      ],
      'line-progress': [
          NumberType,
          [],
          (ctx) => ctx.globals.lineProgress || 0
      ],
      'accumulated': [
          ValueType,
          [],
          (ctx) => ctx.globals.accumulated === undefined ? null : ctx.globals.accumulated
      ],
      '+': [
          NumberType,
          varargs(NumberType),
          (ctx, args) => {
              let result = 0;
              for (const arg of args) {
                  result += arg.evaluate(ctx);
              }
              return result;
          }
      ],
      '*': [
          NumberType,
          varargs(NumberType),
          (ctx, args) => {
              let result = 1;
              for (const arg of args) {
                  result *= arg.evaluate(ctx);
              }
              return result;
          }
      ],
      '-': {
          type: NumberType,
          overloads: [
              [
                  [NumberType, NumberType],
                  (ctx, [a, b]) => a.evaluate(ctx) - b.evaluate(ctx)
              ], [
                  [NumberType],
                  (ctx, [a]) => -a.evaluate(ctx)
              ]
          ]
      },
      '/': [
          NumberType,
          [NumberType, NumberType],
          (ctx, [a, b]) => a.evaluate(ctx) / b.evaluate(ctx)
      ],
      '%': [
          NumberType,
          [NumberType, NumberType],
          (ctx, [a, b]) => a.evaluate(ctx) % b.evaluate(ctx)
      ],
      'ln2': [
          NumberType,
          [],
          () => Math.LN2
      ],
      'pi': [
          NumberType,
          [],
          () => Math.PI
      ],
      'e': [
          NumberType,
          [],
          () => Math.E
      ],
      '^': [
          NumberType,
          [NumberType, NumberType],
          (ctx, [b, e]) => Math.pow(b.evaluate(ctx), e.evaluate(ctx))
      ],
      'sqrt': [
          NumberType,
          [NumberType],
          (ctx, [x]) => Math.sqrt(x.evaluate(ctx))
      ],
      'log10': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.log(n.evaluate(ctx)) / Math.LN10
      ],
      'ln': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.log(n.evaluate(ctx))
      ],
      'log2': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.log(n.evaluate(ctx)) / Math.LN2
      ],
      'sin': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.sin(n.evaluate(ctx))
      ],
      'cos': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.cos(n.evaluate(ctx))
      ],
      'tan': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.tan(n.evaluate(ctx))
      ],
      'asin': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.asin(n.evaluate(ctx))
      ],
      'acos': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.acos(n.evaluate(ctx))
      ],
      'atan': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.atan(n.evaluate(ctx))
      ],
      'min': [
          NumberType,
          varargs(NumberType),
          (ctx, args) => Math.min(...args.map(arg => arg.evaluate(ctx)))
      ],
      'max': [
          NumberType,
          varargs(NumberType),
          (ctx, args) => Math.max(...args.map(arg => arg.evaluate(ctx)))
      ],
      'abs': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.abs(n.evaluate(ctx))
      ],
      'round': [
          NumberType,
          [NumberType],
          (ctx, [n]) => {
              const v = n.evaluate(ctx);
              // Javascript's Math.round() rounds towards +Infinity for halfway
              // values, even when they're negative. It's more common to round
              // away from 0 (e.g., this is what python and C++ do)
              return v < 0 ? -Math.round(-v) : Math.round(v);
          }
      ],
      'floor': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.floor(n.evaluate(ctx))
      ],
      'ceil': [
          NumberType,
          [NumberType],
          (ctx, [n]) => Math.ceil(n.evaluate(ctx))
      ],
      'filter-==': [
          BooleanType,
          [StringType, ValueType],
          (ctx, [k, v]) => ctx.properties()[k.value] === v.value
      ],
      'filter-id-==': [
          BooleanType,
          [ValueType],
          (ctx, [v]) => ctx.id() === v.value
      ],
      'filter-type-==': [
          BooleanType,
          [StringType],
          (ctx, [v]) => ctx.geometryType() === v.value
      ],
      'filter-<': [
          BooleanType,
          [StringType, ValueType],
          (ctx, [k, v]) => {
              const a = ctx.properties()[k.value];
              const b = v.value;
              return typeof a === typeof b && a < b;
          }
      ],
      'filter-id-<': [
          BooleanType,
          [ValueType],
          (ctx, [v]) => {
              const a = ctx.id();
              const b = v.value;
              return typeof a === typeof b && a < b;
          }
      ],
      'filter->': [
          BooleanType,
          [StringType, ValueType],
          (ctx, [k, v]) => {
              const a = ctx.properties()[k.value];
              const b = v.value;
              return typeof a === typeof b && a > b;
          }
      ],
      'filter-id->': [
          BooleanType,
          [ValueType],
          (ctx, [v]) => {
              const a = ctx.id();
              const b = v.value;
              return typeof a === typeof b && a > b;
          }
      ],
      'filter-<=': [
          BooleanType,
          [StringType, ValueType],
          (ctx, [k, v]) => {
              const a = ctx.properties()[k.value];
              const b = v.value;
              return typeof a === typeof b && a <= b;
          }
      ],
      'filter-id-<=': [
          BooleanType,
          [ValueType],
          (ctx, [v]) => {
              const a = ctx.id();
              const b = v.value;
              return typeof a === typeof b && a <= b;
          }
      ],
      'filter->=': [
          BooleanType,
          [StringType, ValueType],
          (ctx, [k, v]) => {
              const a = ctx.properties()[k.value];
              const b = v.value;
              return typeof a === typeof b && a >= b;
          }
      ],
      'filter-id->=': [
          BooleanType,
          [ValueType],
          (ctx, [v]) => {
              const a = ctx.id();
              const b = v.value;
              return typeof a === typeof b && a >= b;
          }
      ],
      'filter-has': [
          BooleanType,
          [ValueType],
          (ctx, [k]) => k.value in ctx.properties()
      ],
      'filter-has-id': [
          BooleanType,
          [],
          (ctx) => (ctx.id() !== null && ctx.id() !== undefined)
      ],
      'filter-type-in': [
          BooleanType,
          [array$1(StringType)],
          (ctx, [v]) => v.value.indexOf(ctx.geometryType()) >= 0
      ],
      'filter-id-in': [
          BooleanType,
          [array$1(ValueType)],
          (ctx, [v]) => v.value.indexOf(ctx.id()) >= 0
      ],
      'filter-in-small': [
          BooleanType,
          [StringType, array$1(ValueType)],
          // assumes v is an array literal
          (ctx, [k, v]) => v.value.indexOf(ctx.properties()[k.value]) >= 0
      ],
      'filter-in-large': [
          BooleanType,
          [StringType, array$1(ValueType)],
          // assumes v is a array literal with values sorted in ascending order and of a single type
          (ctx, [k, v]) => binarySearch(ctx.properties()[k.value], v.value, 0, v.value.length - 1)
      ],
      'all': {
          type: BooleanType,
          overloads: [
              [
                  [BooleanType, BooleanType],
                  (ctx, [a, b]) => a.evaluate(ctx) && b.evaluate(ctx)
              ],
              [
                  varargs(BooleanType),
                  (ctx, args) => {
                      for (const arg of args) {
                          if (!arg.evaluate(ctx))
                              return false;
                      }
                      return true;
                  }
              ]
          ]
      },
      'any': {
          type: BooleanType,
          overloads: [
              [
                  [BooleanType, BooleanType],
                  (ctx, [a, b]) => a.evaluate(ctx) || b.evaluate(ctx)
              ],
              [
                  varargs(BooleanType),
                  (ctx, args) => {
                      for (const arg of args) {
                          if (arg.evaluate(ctx))
                              return true;
                      }
                      return false;
                  }
              ]
          ]
      },
      '!': [
          BooleanType,
          [BooleanType],
          (ctx, [b]) => !b.evaluate(ctx)
      ],
      'is-supported-script': [
          BooleanType,
          [StringType],
          // At parse time this will always return true, so we need to exclude this expression with isGlobalPropertyConstant
          (ctx, [s]) => {
              const isSupportedScript = ctx.globals && ctx.globals.isSupportedScript;
              if (isSupportedScript) {
                  return isSupportedScript(s.evaluate(ctx));
              }
              return true;
          }
      ],
      'upcase': [
          StringType,
          [StringType],
          (ctx, [s]) => s.evaluate(ctx).toUpperCase()
      ],
      'downcase': [
          StringType,
          [StringType],
          (ctx, [s]) => s.evaluate(ctx).toLowerCase()
      ],
      'concat': [
          StringType,
          varargs(ValueType),
          (ctx, args) => args.map(arg => toString(arg.evaluate(ctx))).join('')
      ],
      'resolved-locale': [
          StringType,
          [CollatorType],
          (ctx, [collator]) => collator.evaluate(ctx).resolvedLocale()
      ]
  });

  function success(value) {
      return { result: 'success', value };
  }
  function error(value) {
      return { result: 'error', value };
  }

  function supportsPropertyExpression(spec) {
      return spec['property-type'] === 'data-driven' || spec['property-type'] === 'cross-faded-data-driven';
  }
  function supportsZoomExpression(spec) {
      return !!spec.expression && spec.expression.parameters.indexOf('zoom') > -1;
  }
  function supportsInterpolation(spec) {
      return !!spec.expression && spec.expression.interpolated;
  }

  function getType(val) {
      if (val instanceof Number) {
          return 'number';
      }
      else if (val instanceof String) {
          return 'string';
      }
      else if (val instanceof Boolean) {
          return 'boolean';
      }
      else if (Array.isArray(val)) {
          return 'array';
      }
      else if (val === null) {
          return 'null';
      }
      else {
          return typeof val;
      }
  }

  function isFunction(value) {
      return typeof value === 'object' && value !== null && !Array.isArray(value);
  }
  function identityFunction(x) {
      return x;
  }
  function createFunction(parameters, propertySpec) {
      const isColor = propertySpec.type === 'color';
      const zoomAndFeatureDependent = parameters.stops && typeof parameters.stops[0][0] === 'object';
      const featureDependent = zoomAndFeatureDependent || parameters.property !== undefined;
      const zoomDependent = zoomAndFeatureDependent || !featureDependent;
      const type = parameters.type || (supportsInterpolation(propertySpec) ? 'exponential' : 'interval');
      if (isColor || propertySpec.type === 'padding') {
          const parseFn = isColor ? Color.parse : Padding.parse;
          parameters = extendBy({}, parameters);
          if (parameters.stops) {
              parameters.stops = parameters.stops.map((stop) => {
                  return [stop[0], parseFn(stop[1])];
              });
          }
          if (parameters.default) {
              parameters.default = parseFn(parameters.default);
          }
          else {
              parameters.default = parseFn(propertySpec.default);
          }
      }
      if (parameters.colorSpace && !isSupportedInterpolationColorSpace(parameters.colorSpace)) {
          throw new Error(`Unknown color space: "${parameters.colorSpace}"`);
      }
      let innerFun;
      let hashedStops;
      let categoricalKeyType;
      if (type === 'exponential') {
          innerFun = evaluateExponentialFunction;
      }
      else if (type === 'interval') {
          innerFun = evaluateIntervalFunction;
      }
      else if (type === 'categorical') {
          innerFun = evaluateCategoricalFunction;
          // For categorical functions, generate an Object as a hashmap of the stops for fast searching
          hashedStops = Object.create(null);
          for (const stop of parameters.stops) {
              hashedStops[stop[0]] = stop[1];
          }
          // Infer key type based on first stop key-- used to encforce strict type checking later
          categoricalKeyType = typeof parameters.stops[0][0];
      }
      else if (type === 'identity') {
          innerFun = evaluateIdentityFunction;
      }
      else {
          throw new Error(`Unknown function type "${type}"`);
      }
      if (zoomAndFeatureDependent) {
          const featureFunctions = {};
          const zoomStops = [];
          for (let s = 0; s < parameters.stops.length; s++) {
              const stop = parameters.stops[s];
              const zoom = stop[0].zoom;
              if (featureFunctions[zoom] === undefined) {
                  featureFunctions[zoom] = {
                      zoom,
                      type: parameters.type,
                      property: parameters.property,
                      default: parameters.default,
                      stops: []
                  };
                  zoomStops.push(zoom);
              }
              featureFunctions[zoom].stops.push([stop[0].value, stop[1]]);
          }
          const featureFunctionStops = [];
          for (const z of zoomStops) {
              featureFunctionStops.push([featureFunctions[z].zoom, createFunction(featureFunctions[z], propertySpec)]);
          }
          const interpolationType = { name: 'linear' };
          return {
              kind: 'composite',
              interpolationType,
              interpolationFactor: Interpolate.interpolationFactor.bind(undefined, interpolationType),
              zoomStops: featureFunctionStops.map(s => s[0]),
              evaluate({ zoom }, properties) {
                  return evaluateExponentialFunction({
                      stops: featureFunctionStops,
                      base: parameters.base
                  }, propertySpec, zoom).evaluate(zoom, properties);
              }
          };
      }
      else if (zoomDependent) {
          const interpolationType = type === 'exponential' ?
              { name: 'exponential', base: parameters.base !== undefined ? parameters.base : 1 } : null;
          return {
              kind: 'camera',
              interpolationType,
              interpolationFactor: Interpolate.interpolationFactor.bind(undefined, interpolationType),
              zoomStops: parameters.stops.map(s => s[0]),
              evaluate: ({ zoom }) => innerFun(parameters, propertySpec, zoom, hashedStops, categoricalKeyType)
          };
      }
      else {
          return {
              kind: 'source',
              evaluate(_, feature) {
                  const value = feature && feature.properties ? feature.properties[parameters.property] : undefined;
                  if (value === undefined) {
                      return coalesce$1(parameters.default, propertySpec.default);
                  }
                  return innerFun(parameters, propertySpec, value, hashedStops, categoricalKeyType);
              }
          };
      }
  }
  function coalesce$1(a, b, c) {
      if (a !== undefined)
          return a;
      if (b !== undefined)
          return b;
      if (c !== undefined)
          return c;
  }
  function evaluateCategoricalFunction(parameters, propertySpec, input, hashedStops, keyType) {
      const evaluated = typeof input === keyType ? hashedStops[input] : undefined; // Enforce strict typing on input
      return coalesce$1(evaluated, parameters.default, propertySpec.default);
  }
  function evaluateIntervalFunction(parameters, propertySpec, input) {
      // Edge cases
      if (getType(input) !== 'number')
          return coalesce$1(parameters.default, propertySpec.default);
      const n = parameters.stops.length;
      if (n === 1)
          return parameters.stops[0][1];
      if (input <= parameters.stops[0][0])
          return parameters.stops[0][1];
      if (input >= parameters.stops[n - 1][0])
          return parameters.stops[n - 1][1];
      const index = findStopLessThanOrEqualTo(parameters.stops.map((stop) => stop[0]), input);
      return parameters.stops[index][1];
  }
  function evaluateExponentialFunction(parameters, propertySpec, input) {
      const base = parameters.base !== undefined ? parameters.base : 1;
      // Edge cases
      if (getType(input) !== 'number')
          return coalesce$1(parameters.default, propertySpec.default);
      const n = parameters.stops.length;
      if (n === 1)
          return parameters.stops[0][1];
      if (input <= parameters.stops[0][0])
          return parameters.stops[0][1];
      if (input >= parameters.stops[n - 1][0])
          return parameters.stops[n - 1][1];
      const index = findStopLessThanOrEqualTo(parameters.stops.map((stop) => stop[0]), input);
      const t = interpolationFactor(input, base, parameters.stops[index][0], parameters.stops[index + 1][0]);
      const outputLower = parameters.stops[index][1];
      const outputUpper = parameters.stops[index + 1][1];
      const interp = interpolate[propertySpec.type] || identityFunction;
      if (typeof outputLower.evaluate === 'function') {
          return {
              evaluate(...args) {
                  const evaluatedLower = outputLower.evaluate.apply(undefined, args);
                  const evaluatedUpper = outputUpper.evaluate.apply(undefined, args);
                  // Special case for fill-outline-color, which has no spec default.
                  if (evaluatedLower === undefined || evaluatedUpper === undefined) {
                      return undefined;
                  }
                  return interp(evaluatedLower, evaluatedUpper, t, parameters.colorSpace);
              }
          };
      }
      return interp(outputLower, outputUpper, t, parameters.colorSpace);
  }
  function evaluateIdentityFunction(parameters, propertySpec, input) {
      switch (propertySpec.type) {
          case 'color':
              input = Color.parse(input);
              break;
          case 'formatted':
              input = Formatted.fromString(input.toString());
              break;
          case 'resolvedImage':
              input = ResolvedImage.fromString(input.toString());
              break;
          case 'padding':
              input = Padding.parse(input);
              break;
          default:
              if (getType(input) !== propertySpec.type && (propertySpec.type !== 'enum' || !propertySpec.values[input])) {
                  input = undefined;
              }
      }
      return coalesce$1(input, parameters.default, propertySpec.default);
  }
  /**
   * Returns a ratio that can be used to interpolate between exponential function
   * stops.
   *
   * How it works:
   * Two consecutive stop values define a (scaled and shifted) exponential
   * function `f(x) = a * base^x + b`, where `base` is the user-specified base,
   * and `a` and `b` are constants affording sufficient degrees of freedom to fit
   * the function to the given stops.
   *
   * Here's a bit of algebra that lets us compute `f(x)` directly from the stop
   * values without explicitly solving for `a` and `b`:
   *
   * First stop value: `f(x0) = y0 = a * base^x0 + b`
   * Second stop value: `f(x1) = y1 = a * base^x1 + b`
   * => `y1 - y0 = a(base^x1 - base^x0)`
   * => `a = (y1 - y0)/(base^x1 - base^x0)`
   *
   * Desired value: `f(x) = y = a * base^x + b`
   * => `f(x) = y0 + a * (base^x - base^x0)`
   *
   * From the above, we can replace the `a` in `a * (base^x - base^x0)` and do a
   * little algebra:
   * ```
   * a * (base^x - base^x0) = (y1 - y0)/(base^x1 - base^x0) * (base^x - base^x0)
   *                     = (y1 - y0) * (base^x - base^x0) / (base^x1 - base^x0)
   * ```
   *
   * If we let `(base^x - base^x0) / (base^x1 base^x0)`, then we have
   * `f(x) = y0 + (y1 - y0) * ratio`.  In other words, `ratio` may be treated as
   * an interpolation factor between the two stops' output values.
   *
   * (Note: a slightly different form for `ratio`,
   * `(base^(x-x0) - 1) / (base^(x1-x0) - 1) `, is equivalent, but requires fewer
   * expensive `Math.pow()` operations.)
   *
   * @private
   */
  function interpolationFactor(input, base, lowerValue, upperValue) {
      const difference = upperValue - lowerValue;
      const progress = input - lowerValue;
      if (difference === 0) {
          return 0;
      }
      else if (base === 1) {
          return progress / difference;
      }
      else {
          return (Math.pow(base, progress) - 1) / (Math.pow(base, difference) - 1);
      }
  }

  class StyleExpression {
      constructor(expression, propertySpec) {
          this.expression = expression;
          this._warningHistory = {};
          this._evaluator = new EvaluationContext();
          this._defaultValue = propertySpec ? getDefaultValue(propertySpec) : null;
          this._enumValues = propertySpec && propertySpec.type === 'enum' ? propertySpec.values : null;
      }
      evaluateWithoutErrorHandling(globals, feature, featureState, canonical, availableImages, formattedSection) {
          this._evaluator.globals = globals;
          this._evaluator.feature = feature;
          this._evaluator.featureState = featureState;
          this._evaluator.canonical = canonical;
          this._evaluator.availableImages = availableImages || null;
          this._evaluator.formattedSection = formattedSection;
          return this.expression.evaluate(this._evaluator);
      }
      evaluate(globals, feature, featureState, canonical, availableImages, formattedSection) {
          this._evaluator.globals = globals;
          this._evaluator.feature = feature || null;
          this._evaluator.featureState = featureState || null;
          this._evaluator.canonical = canonical;
          this._evaluator.availableImages = availableImages || null;
          this._evaluator.formattedSection = formattedSection || null;
          try {
              const val = this.expression.evaluate(this._evaluator);
              // eslint-disable-next-line no-self-compare
              if (val === null || val === undefined || (typeof val === 'number' && val !== val)) {
                  return this._defaultValue;
              }
              if (this._enumValues && !(val in this._enumValues)) {
                  throw new RuntimeError(`Expected value to be one of ${Object.keys(this._enumValues).map(v => JSON.stringify(v)).join(', ')}, but found ${JSON.stringify(val)} instead.`);
              }
              return val;
          }
          catch (e) {
              if (!this._warningHistory[e.message]) {
                  this._warningHistory[e.message] = true;
                  if (typeof console !== 'undefined') {
                      console.warn(e.message);
                  }
              }
              return this._defaultValue;
          }
      }
  }
  function isExpression(expression) {
      return Array.isArray(expression) && expression.length > 0 &&
          typeof expression[0] === 'string' && expression[0] in expressions;
  }
  /**
   * Parse and typecheck the given style spec JSON expression.  If
   * options.defaultValue is provided, then the resulting StyleExpression's
   * `evaluate()` method will handle errors by logging a warning (once per
   * message) and returning the default value.  Otherwise, it will throw
   * evaluation errors.
   *
   * @private
   */
  function createExpression(expression, propertySpec) {
      const parser = new ParsingContext(expressions, isExpressionConstant, [], propertySpec ? getExpectedType(propertySpec) : undefined);
      // For string-valued properties, coerce to string at the top level rather than asserting.
      const parsed = parser.parse(expression, undefined, undefined, undefined, propertySpec && propertySpec.type === 'string' ? { typeAnnotation: 'coerce' } : undefined);
      if (!parsed) {
          return error(parser.errors);
      }
      return success(new StyleExpression(parsed, propertySpec));
  }
  class ZoomConstantExpression {
      constructor(kind, expression) {
          this.kind = kind;
          this._styleExpression = expression;
          this.isStateDependent = kind !== 'constant' && !isStateConstant(expression.expression);
      }
      evaluateWithoutErrorHandling(globals, feature, featureState, canonical, availableImages, formattedSection) {
          return this._styleExpression.evaluateWithoutErrorHandling(globals, feature, featureState, canonical, availableImages, formattedSection);
      }
      evaluate(globals, feature, featureState, canonical, availableImages, formattedSection) {
          return this._styleExpression.evaluate(globals, feature, featureState, canonical, availableImages, formattedSection);
      }
  }
  class ZoomDependentExpression {
      constructor(kind, expression, zoomStops, interpolationType) {
          this.kind = kind;
          this.zoomStops = zoomStops;
          this._styleExpression = expression;
          this.isStateDependent = kind !== 'camera' && !isStateConstant(expression.expression);
          this.interpolationType = interpolationType;
      }
      evaluateWithoutErrorHandling(globals, feature, featureState, canonical, availableImages, formattedSection) {
          return this._styleExpression.evaluateWithoutErrorHandling(globals, feature, featureState, canonical, availableImages, formattedSection);
      }
      evaluate(globals, feature, featureState, canonical, availableImages, formattedSection) {
          return this._styleExpression.evaluate(globals, feature, featureState, canonical, availableImages, formattedSection);
      }
      interpolationFactor(input, lower, upper) {
          if (this.interpolationType) {
              return Interpolate.interpolationFactor(this.interpolationType, input, lower, upper);
          }
          else {
              return 0;
          }
      }
  }
  function isZoomExpression(expression) {
      return expression._styleExpression !== undefined;
  }
  function createPropertyExpression(expressionInput, propertySpec) {
      const expression = createExpression(expressionInput, propertySpec);
      if (expression.result === 'error') {
          return expression;
      }
      const parsed = expression.value.expression;
      const isFeatureConstantResult = isFeatureConstant(parsed);
      if (!isFeatureConstantResult && !supportsPropertyExpression(propertySpec)) {
          return error([new ExpressionParsingError('', 'data expressions not supported')]);
      }
      const isZoomConstant = isGlobalPropertyConstant(parsed, ['zoom']);
      if (!isZoomConstant && !supportsZoomExpression(propertySpec)) {
          return error([new ExpressionParsingError('', 'zoom expressions not supported')]);
      }
      const zoomCurve = findZoomCurve(parsed);
      if (!zoomCurve && !isZoomConstant) {
          return error([new ExpressionParsingError('', '"zoom" expression may only be used as input to a top-level "step" or "interpolate" expression.')]);
      }
      else if (zoomCurve instanceof ExpressionParsingError) {
          return error([zoomCurve]);
      }
      else if (zoomCurve instanceof Interpolate && !supportsInterpolation(propertySpec)) {
          return error([new ExpressionParsingError('', '"interpolate" expressions cannot be used with this property')]);
      }
      if (!zoomCurve) {
          return success(isFeatureConstantResult ?
              new ZoomConstantExpression('constant', expression.value) :
              new ZoomConstantExpression('source', expression.value));
      }
      const interpolationType = zoomCurve instanceof Interpolate ? zoomCurve.interpolation : undefined;
      return success(isFeatureConstantResult ?
          new ZoomDependentExpression('camera', expression.value, zoomCurve.labels, interpolationType) :
          new ZoomDependentExpression('composite', expression.value, zoomCurve.labels, interpolationType));
  }
  // serialization wrapper for old-style stop functions normalized to the
  // expression interface
  class StylePropertyFunction {
      constructor(parameters, specification) {
          this._parameters = parameters;
          this._specification = specification;
          extendBy(this, createFunction(this._parameters, this._specification));
      }
      static deserialize(serialized) {
          return new StylePropertyFunction(serialized._parameters, serialized._specification);
      }
      static serialize(input) {
          return {
              _parameters: input._parameters,
              _specification: input._specification
          };
      }
  }
  function normalizePropertyExpression(value, specification) {
      if (isFunction(value)) {
          return new StylePropertyFunction(value, specification);
      }
      else if (isExpression(value)) {
          const expression = createPropertyExpression(value, specification);
          if (expression.result === 'error') {
              // this should have been caught in validation
              throw new Error(expression.value.map(err => `${err.key}: ${err.message}`).join(', '));
          }
          return expression.value;
      }
      else {
          let constant = value;
          if (specification.type === 'color' && typeof value === 'string') {
              constant = Color.parse(value);
          }
          else if (specification.type === 'padding' && (typeof value === 'number' || Array.isArray(value))) {
              constant = Padding.parse(value);
          }
          else if (specification.type === 'variableAnchorOffsetCollection' && Array.isArray(value)) {
              constant = VariableAnchorOffsetCollection.parse(value);
          }
          return {
              kind: 'constant',
              evaluate: () => constant
          };
      }
  }
  // Zoom-dependent expressions may only use ["zoom"] as the input to a top-level "step" or "interpolate"
  // expression (collectively referred to as a "curve"). The curve may be wrapped in one or more "let" or
  // "coalesce" expressions.
  function findZoomCurve(expression) {
      let result = null;
      if (expression instanceof Let) {
          result = findZoomCurve(expression.result);
      }
      else if (expression instanceof Coalesce) {
          for (const arg of expression.args) {
              result = findZoomCurve(arg);
              if (result) {
                  break;
              }
          }
      }
      else if ((expression instanceof Step || expression instanceof Interpolate) &&
          expression.input instanceof CompoundExpression &&
          expression.input.name === 'zoom') {
          result = expression;
      }
      if (result instanceof ExpressionParsingError) {
          return result;
      }
      expression.eachChild((child) => {
          const childResult = findZoomCurve(child);
          if (childResult instanceof ExpressionParsingError) {
              result = childResult;
          }
          else if (!result && childResult) {
              result = new ExpressionParsingError('', '"zoom" expression may only be used as input to a top-level "step" or "interpolate" expression.');
          }
          else if (result && childResult && result !== childResult) {
              result = new ExpressionParsingError('', 'Only one zoom-based "step" or "interpolate" subexpression may be used in an expression.');
          }
      });
      return result;
  }
  function getExpectedType(spec) {
      const types = {
          color: ColorType,
          string: StringType,
          number: NumberType,
          enum: StringType,
          boolean: BooleanType,
          formatted: FormattedType,
          padding: PaddingType,
          resolvedImage: ResolvedImageType,
          variableAnchorOffsetCollection: VariableAnchorOffsetCollectionType
      };
      if (spec.type === 'array') {
          return array$1(types[spec.value] || ValueType, spec.length);
      }
      return types[spec.type];
  }
  function getDefaultValue(spec) {
      if (spec.type === 'color' && isFunction(spec.default)) {
          // Special case for heatmap-color: it uses the 'default:' to define a
          // default color ramp, but createExpression expects a simple value to fall
          // back to in case of runtime errors
          return new Color(0, 0, 0, 0);
      }
      else if (spec.type === 'color') {
          return Color.parse(spec.default) || null;
      }
      else if (spec.type === 'padding') {
          return Padding.parse(spec.default) || null;
      }
      else if (spec.type === 'variableAnchorOffsetCollection') {
          return VariableAnchorOffsetCollection.parse(spec.default) || null;
      }
      else if (spec.default === undefined) {
          return null;
      }
      else {
          return spec.default;
      }
  }

  function isExpressionFilter(filter) {
      if (filter === true || filter === false) {
          return true;
      }
      if (!Array.isArray(filter) || filter.length === 0) {
          return false;
      }
      switch (filter[0]) {
          case 'has':
              return filter.length >= 2 && filter[1] !== '$id' && filter[1] !== '$type';
          case 'in':
              return filter.length >= 3 && (typeof filter[1] !== 'string' || Array.isArray(filter[2]));
          case '!in':
          case '!has':
          case 'none':
              return false;
          case '==':
          case '!=':
          case '>':
          case '>=':
          case '<':
          case '<=':
              return filter.length !== 3 || (Array.isArray(filter[1]) || Array.isArray(filter[2]));
          case 'any':
          case 'all':
              for (const f of filter.slice(1)) {
                  if (!isExpressionFilter(f) && typeof f !== 'boolean') {
                      return false;
                  }
              }
              return true;
          default:
              return true;
      }
  }
  const filterSpec = {
      'type': 'boolean',
      'default': false,
      'transition': false,
      'property-type': 'data-driven',
      'expression': {
          'interpolated': false,
          'parameters': ['zoom', 'feature']
      }
  };
  /**
   * Given a filter expressed as nested arrays, return a new function
   * that evaluates whether a given feature (with a .properties or .tags property)
   * passes its test.
   *
   * @private
   * @param {Array} filter MapLibre filter
   * @returns {Function} filter-evaluating function
   */
  function createFilter(filter) {
      if (filter === null || filter === undefined) {
          return { filter: () => true, needGeometry: false };
      }
      if (!isExpressionFilter(filter)) {
          filter = convertFilter$1(filter);
      }
      const compiled = createExpression(filter, filterSpec);
      if (compiled.result === 'error') {
          throw new Error(compiled.value.map(err => `${err.key}: ${err.message}`).join(', '));
      }
      else {
          const needGeometry = geometryNeeded(filter);
          return { filter: (globalProperties, feature, canonical) => compiled.value.evaluate(globalProperties, feature, {}, canonical),
              needGeometry };
      }
  }
  // Comparison function to sort numbers and strings
  function compare(a, b) {
      return a < b ? -1 : a > b ? 1 : 0;
  }
  function geometryNeeded(filter) {
      if (!Array.isArray(filter))
          return false;
      if (filter[0] === 'within')
          return true;
      for (let index = 1; index < filter.length; index++) {
          if (geometryNeeded(filter[index]))
              return true;
      }
      return false;
  }
  function convertFilter$1(filter) {
      if (!filter)
          return true;
      const op = filter[0];
      if (filter.length <= 1)
          return (op !== 'any');
      const converted = op === '==' ? convertComparisonOp$1(filter[1], filter[2], '==') :
          op === '!=' ? convertNegation(convertComparisonOp$1(filter[1], filter[2], '==')) :
              op === '<' ||
                  op === '>' ||
                  op === '<=' ||
                  op === '>=' ? convertComparisonOp$1(filter[1], filter[2], op) :
                  op === 'any' ? convertDisjunctionOp(filter.slice(1)) :
                      op === 'all' ? ['all'].concat(filter.slice(1).map(convertFilter$1)) :
                          op === 'none' ? ['all'].concat(filter.slice(1).map(convertFilter$1).map(convertNegation)) :
                              op === 'in' ? convertInOp$1(filter[1], filter.slice(2)) :
                                  op === '!in' ? convertNegation(convertInOp$1(filter[1], filter.slice(2))) :
                                      op === 'has' ? convertHasOp$1(filter[1]) :
                                          op === '!has' ? convertNegation(convertHasOp$1(filter[1])) :
                                              op === 'within' ? filter :
                                                  true;
      return converted;
  }
  function convertComparisonOp$1(property, value, op) {
      switch (property) {
          case '$type':
              return [`filter-type-${op}`, value];
          case '$id':
              return [`filter-id-${op}`, value];
          default:
              return [`filter-${op}`, property, value];
      }
  }
  function convertDisjunctionOp(filters) {
      return ['any'].concat(filters.map(convertFilter$1));
  }
  function convertInOp$1(property, values) {
      if (values.length === 0) {
          return false;
      }
      switch (property) {
          case '$type':
              return ['filter-type-in', ['literal', values]];
          case '$id':
              return ['filter-id-in', ['literal', values]];
          default:
              if (values.length > 200 && !values.some(v => typeof v !== typeof values[0])) {
                  return ['filter-in-large', property, ['literal', values.sort(compare)]];
              }
              else {
                  return ['filter-in-small', property, ['literal', values]];
              }
      }
  }
  function convertHasOp$1(property) {
      switch (property) {
          case '$type':
              return true;
          case '$id':
              return ['filter-has-id'];
          default:
              return ['filter-has', property];
      }
  }
  function convertNegation(filter) {
      return ['!', filter];
  }

  /*
   * Convert the given filter to an expression, storing the expected types for
   * any feature properties referenced in expectedTypes.
   *
   * These expected types are needed in order to construct preflight type checks
   * needed for handling 'any' filters. A preflight type check is necessary in
   * order to mimic legacy filters' semantics around expected type mismatches.
   * For example, consider the legacy filter:
   *
   *     ["any", ["all", [">", "y", 0], [">", "y", 0]], [">", "x", 0]]
   *
   * Naively, we might convert this to the expression:
   *
   *     ["any", ["all", [">", ["get", "y"], 0], [">", ["get", "z"], 0]], [">", ["get", "x"], 0]]
   *
   * But if we tried to evaluate this against, say `{x: 1, y: null, z: 0}`, the
   * [">", ["get", "y"], 0] would cause an evaluation error, leading to the
   * entire filter returning false. Legacy filter semantics, though, ask for
   * [">", "y", 0] to simply return `false` when `y` is of the wrong type,
   * allowing the subsequent terms of the outer "any" expression to be evaluated
   * (resulting, in this case, in a `true` value, because x > 0).
   *
   * We account for this by inserting a preflight type-checking expression before
   * each "any" term, allowing us to avoid evaluating the actual converted filter
   * if any type mismatches would cause it to produce an evalaution error:
   *
   *     ["any",
   *       ["case",
   *         ["all", ["==", ["typeof", ["get", "y"]], "number"], ["==", ["typeof", ["get", "z"], "number]],
   *         ["all", [">", ["get", "y"], 0], [">", ["get", "z"], 0]],
   *         false
   *       ],
   *       ["case",
   *         ["==", ["typeof", ["get", "x"], "number"]],
   *         [">", ["get", "x"], 0],
   *         false
   *       ]
   *     ]
   *
   * An alternative, possibly more direct approach would be to use type checks
   * in the conversion of each comparison operator, so that the converted version
   * of each individual ==, >=, etc. would mimic the legacy filter semantics. The
   * downside of this approach is that it can lead to many more type checks than
   * would otherwise be necessary: outside the context of an "any" expression,
   * bailing out due to a runtime type error (expression semantics) and returning
   * false (legacy filter semantics) are equivalent: they cause the filter to
   * produce a `false` result.
   */
  function convertFilter(filter, expectedTypes = {}) {
      if (isExpressionFilter(filter))
          return filter;
      if (!filter)
          return true;
      const legacyFilter = filter;
      const legacyOp = legacyFilter[0];
      if (filter.length <= 1)
          return (legacyOp !== 'any');
      switch (legacyOp) {
          case '==':
          case '!=':
          case '<':
          case '>':
          case '<=':
          case '>=': {
              const [, property, value] = filter;
              return convertComparisonOp(property, value, legacyOp, expectedTypes);
          }
          case 'any': {
              const [, ...conditions] = legacyFilter;
              const children = conditions.map((f) => {
                  const types = {};
                  const child = convertFilter(f, types);
                  const typechecks = runtimeTypeChecks(types);
                  return typechecks === true ? child : ['case', typechecks, child, false];
              });
              return ['any', ...children];
          }
          case 'all': {
              const [, ...conditions] = legacyFilter;
              const children = conditions.map(f => convertFilter(f, expectedTypes));
              return children.length > 1 ? ['all', ...children] : children[0];
          }
          case 'none': {
              const [, ...conditions] = legacyFilter;
              return ['!', convertFilter(['any', ...conditions], {})];
          }
          case 'in': {
              const [, property, ...values] = legacyFilter;
              return convertInOp(property, values);
          }
          case '!in': {
              const [, property, ...values] = legacyFilter;
              return convertInOp(property, values, true);
          }
          case 'has':
              return convertHasOp(legacyFilter[1]);
          case '!has':
              return ['!', convertHasOp(legacyFilter[1])];
          default:
              return true;
      }
  }
  // Given a set of feature properties and an expected type for each one,
  // construct an boolean expression that tests whether each property has the
  // right type.
  // E.g.: for {name: 'string', population: 'number'}, return
  // [ 'all',
  //   ['==', ['typeof', ['get', 'name'], 'string']],
  //   ['==', ['typeof', ['get', 'population'], 'number]]
  // ]
  function runtimeTypeChecks(expectedTypes) {
      const conditions = [];
      for (const property in expectedTypes) {
          const get = property === '$id' ? ['id'] : ['get', property];
          conditions.push(['==', ['typeof', get], expectedTypes[property]]);
      }
      if (conditions.length === 0)
          return true;
      if (conditions.length === 1)
          return conditions[0];
      return ['all', ...conditions];
  }
  function convertComparisonOp(property, value, op, expectedTypes) {
      let get;
      if (property === '$type') {
          return [op, ['geometry-type'], value];
      }
      else if (property === '$id') {
          get = ['id'];
      }
      else {
          get = ['get', property];
      }
      if (expectedTypes && value !== null) {
          const type = typeof value;
          expectedTypes[property] = type;
      }
      if (op === '==' && property !== '$id' && value === null) {
          return [
              'all',
              ['has', property],
              ['==', get, null]
          ];
      }
      else if (op === '!=' && property !== '$id' && value === null) {
          return [
              'any',
              ['!', ['has', property]],
              ['!=', get, null]
          ];
      }
      return [op, get, value];
  }
  function convertInOp(property, values, negate = false) {
      if (values.length === 0)
          return negate;
      let get;
      if (property === '$type') {
          get = ['geometry-type'];
      }
      else if (property === '$id') {
          get = ['id'];
      }
      else {
          get = ['get', property];
      }
      // Determine if the list of values to be searched is homogenously typed.
      // If so (and if the type is string or number), then we can use a
      // [match, input, [...values], true, false] construction rather than a
      // bunch of `==` tests.
      let uniformTypes = true;
      const type = typeof values[0];
      for (const value of values) {
          if (typeof value !== type) {
              uniformTypes = false;
              break;
          }
      }
      if (uniformTypes && (type === 'string' || type === 'number')) {
          // Match expressions must have unique values.
          const uniqueValues = values.sort().filter((v, i) => i === 0 || values[i - 1] !== v);
          return ['match', get, uniqueValues, !negate, negate];
      }
      if (negate) {
          return ['all', ...values.map(v => ['!=', get, v])];
      }
      else {
          return ['any', ...values.map(v => ['==', get, v])];
      }
  }
  function convertHasOp(property) {
      if (property === '$type') {
          return true;
      }
      else if (property === '$id') {
          return ['!=', ['id'], null];
      }
      else {
          return ['has', property];
      }
  }

  function convertLiteral(value) {
      return typeof value === 'object' ? ['literal', value] : value;
  }
  function convertFunction(parameters, propertySpec) {
      let stops = parameters.stops;
      if (!stops) {
          // identity function
          return convertIdentityFunction(parameters, propertySpec);
      }
      const zoomAndFeatureDependent = stops && typeof stops[0][0] === 'object';
      const featureDependent = zoomAndFeatureDependent || parameters.property !== undefined;
      const zoomDependent = zoomAndFeatureDependent || !featureDependent;
      stops = stops.map((stop) => {
          if (!featureDependent && propertySpec.tokens && typeof stop[1] === 'string') {
              return [stop[0], convertTokenString(stop[1])];
          }
          return [stop[0], convertLiteral(stop[1])];
      });
      if (zoomAndFeatureDependent) {
          return convertZoomAndPropertyFunction(parameters, propertySpec, stops);
      }
      else if (zoomDependent) {
          return convertZoomFunction(parameters, propertySpec, stops);
      }
      else {
          return convertPropertyFunction(parameters, propertySpec, stops);
      }
  }
  function convertIdentityFunction(parameters, propertySpec) {
      const get = ['get', parameters.property];
      if (parameters.default === undefined) {
          // By default, expressions for string-valued properties get coerced. To preserve
          // legacy function semantics, insert an explicit assertion instead.
          return propertySpec.type === 'string' ? ['string', get] : get;
      }
      else if (propertySpec.type === 'enum') {
          return [
              'match',
              get,
              Object.keys(propertySpec.values),
              get,
              parameters.default
          ];
      }
      else {
          const expression = [propertySpec.type === 'color' ? 'to-color' : propertySpec.type, get, convertLiteral(parameters.default)];
          if (propertySpec.type === 'array') {
              expression.splice(1, 0, propertySpec.value, propertySpec.length || null);
          }
          return expression;
      }
  }
  function getInterpolateOperator(parameters) {
      switch (parameters.colorSpace) {
          case 'hcl': return 'interpolate-hcl';
          case 'lab': return 'interpolate-lab';
          default: return 'interpolate';
      }
  }
  function convertZoomAndPropertyFunction(parameters, propertySpec, stops) {
      const featureFunctionParameters = {};
      const featureFunctionStops = {};
      const zoomStops = [];
      for (let s = 0; s < stops.length; s++) {
          const stop = stops[s];
          const zoom = stop[0].zoom;
          if (featureFunctionParameters[zoom] === undefined) {
              featureFunctionParameters[zoom] = {
                  zoom,
                  type: parameters.type,
                  property: parameters.property,
                  default: parameters.default,
              };
              featureFunctionStops[zoom] = [];
              zoomStops.push(zoom);
          }
          featureFunctionStops[zoom].push([stop[0].value, stop[1]]);
      }
      // the interpolation type for the zoom dimension of a zoom-and-property
      // function is determined directly from the style property specification
      // for which it's being used: linear for interpolatable properties, step
      // otherwise.
      const functionType = getFunctionType({}, propertySpec);
      if (functionType === 'exponential') {
          const expression = [getInterpolateOperator(parameters), ['linear'], ['zoom']];
          for (const z of zoomStops) {
              const output = convertPropertyFunction(featureFunctionParameters[z], propertySpec, featureFunctionStops[z]);
              appendStopPair(expression, z, output, false);
          }
          return expression;
      }
      else {
          const expression = ['step', ['zoom']];
          for (const z of zoomStops) {
              const output = convertPropertyFunction(featureFunctionParameters[z], propertySpec, featureFunctionStops[z]);
              appendStopPair(expression, z, output, true);
          }
          fixupDegenerateStepCurve(expression);
          return expression;
      }
  }
  function coalesce(a, b) {
      if (a !== undefined)
          return a;
      if (b !== undefined)
          return b;
  }
  function getFallback(parameters, propertySpec) {
      const defaultValue = convertLiteral(coalesce(parameters.default, propertySpec.default));
      /*
       * Some fields with type: resolvedImage have an undefined default.
       * Because undefined is an invalid value for resolvedImage, set fallback to
       * an empty string instead of undefined to ensure output
       * passes validation.
       */
      if (defaultValue === undefined && propertySpec.type === 'resolvedImage') {
          return '';
      }
      return defaultValue;
  }
  function convertPropertyFunction(parameters, propertySpec, stops) {
      const type = getFunctionType(parameters, propertySpec);
      const get = ['get', parameters.property];
      if (type === 'categorical' && typeof stops[0][0] === 'boolean') {
          const expression = ['case'];
          for (const stop of stops) {
              expression.push(['==', get, stop[0]], stop[1]);
          }
          expression.push(getFallback(parameters, propertySpec));
          return expression;
      }
      else if (type === 'categorical') {
          const expression = ['match', get];
          for (const stop of stops) {
              appendStopPair(expression, stop[0], stop[1], false);
          }
          expression.push(getFallback(parameters, propertySpec));
          return expression;
      }
      else if (type === 'interval') {
          const expression = ['step', ['number', get]];
          for (const stop of stops) {
              appendStopPair(expression, stop[0], stop[1], true);
          }
          fixupDegenerateStepCurve(expression);
          return parameters.default === undefined ? expression : [
              'case',
              ['==', ['typeof', get], 'number'],
              expression,
              convertLiteral(parameters.default)
          ];
      }
      else if (type === 'exponential') {
          const base = parameters.base !== undefined ? parameters.base : 1;
          const expression = [
              getInterpolateOperator(parameters),
              base === 1 ? ['linear'] : ['exponential', base],
              ['number', get]
          ];
          for (const stop of stops) {
              appendStopPair(expression, stop[0], stop[1], false);
          }
          return parameters.default === undefined ? expression : [
              'case',
              ['==', ['typeof', get], 'number'],
              expression,
              convertLiteral(parameters.default)
          ];
      }
      else {
          throw new Error(`Unknown property function type ${type}`);
      }
  }
  function convertZoomFunction(parameters, propertySpec, stops, input = ['zoom']) {
      const type = getFunctionType(parameters, propertySpec);
      let expression;
      let isStep = false;
      if (type === 'interval') {
          expression = ['step', input];
          isStep = true;
      }
      else if (type === 'exponential') {
          const base = parameters.base !== undefined ? parameters.base : 1;
          expression = [getInterpolateOperator(parameters), base === 1 ? ['linear'] : ['exponential', base], input];
      }
      else {
          throw new Error(`Unknown zoom function type "${type}"`);
      }
      for (const stop of stops) {
          appendStopPair(expression, stop[0], stop[1], isStep);
      }
      fixupDegenerateStepCurve(expression);
      return expression;
  }
  function fixupDegenerateStepCurve(expression) {
      // degenerate step curve (i.e. a constant function): add a noop stop
      if (expression[0] === 'step' && expression.length === 3) {
          expression.push(0);
          expression.push(expression[3]);
      }
  }
  function appendStopPair(curve, input, output, isStep) {
      // Skip duplicate stop values. They were not validated for functions, but they are for expressions.
      // https://github.com/mapbox/mapbox-gl-js/issues/4107
      if (curve.length > 3 && input === curve[curve.length - 2]) {
          return;
      }
      // step curves don't get the first input value, as it is redundant.
      if (!(isStep && curve.length === 2)) {
          curve.push(input);
      }
      curve.push(output);
  }
  function getFunctionType(parameters, propertySpec) {
      if (parameters.type) {
          return parameters.type;
      }
      else {
          return propertySpec.expression.interpolated ? 'exponential' : 'interval';
      }
  }
  // "String with {name} token" => ["concat", "String with ", ["get", "name"], " token"]
  function convertTokenString(s) {
      const result = ['concat'];
      const re = /{([^{}]+)}/g;
      let pos = 0;
      for (let match = re.exec(s); match !== null; match = re.exec(s)) {
          const literal = s.slice(pos, re.lastIndex - match[0].length);
          pos = re.lastIndex;
          if (literal.length > 0)
              result.push(literal);
          result.push(['get', match[1]]);
      }
      if (result.length === 1) {
          return s;
      }
      if (pos < s.length) {
          result.push(s.slice(pos));
      }
      else if (result.length === 2) {
          return ['to-string', result[1]];
      }
      return result;
  }

  function getPropertyReference(propertyName) {
      for (let i = 0; i < v8Spec.layout.length; i++) {
          for (const key in v8Spec[v8Spec.layout[i]]) {
              if (key === propertyName)
                  return v8Spec[v8Spec.layout[i]][key];
          }
      }
      for (let i = 0; i < v8Spec.paint.length; i++) {
          for (const key in v8Spec[v8Spec.paint[i]]) {
              if (key === propertyName)
                  return v8Spec[v8Spec.paint[i]][key];
          }
      }
      return null;
  }
  function eachSource(style, callback) {
      for (const k in style.sources) {
          callback(style.sources[k]);
      }
  }
  function eachLayer(style, callback) {
      for (const layer of style.layers) {
          callback(layer);
      }
  }
  function eachProperty(style, options, callback) {
      function inner(layer, propertyType) {
          const properties = layer[propertyType];
          if (!properties)
              return;
          Object.keys(properties).forEach((key) => {
              callback({
                  path: [layer.id, propertyType, key],
                  key,
                  value: properties[key],
                  reference: getPropertyReference(key),
                  set(x) {
                      properties[key] = x;
                  }
              });
          });
      }
      eachLayer(style, (layer) => {
          if (options.paint) {
              inner(layer, 'paint');
          }
          if (options.layout) {
              inner(layer, 'layout');
          }
      });
  }

  function stringify(obj) {
      const type = typeof obj;
      if (type === 'number' || type === 'boolean' || type === 'string' || obj === undefined || obj === null)
          return JSON.stringify(obj);
      if (Array.isArray(obj)) {
          let str = '[';
          for (const val of obj) {
              str += `${stringify(val)},`;
          }
          return `${str}]`;
      }
      const keys = Object.keys(obj).sort();
      let str = '{';
      for (let i = 0; i < keys.length; i++) {
          str += `${JSON.stringify(keys[i])}:${stringify(obj[keys[i]])},`;
      }
      return `${str}}`;
  }
  function getKey(layer) {
      let key = '';
      for (const k of refProperties) {
          key += `/${stringify(layer[k])}`;
      }
      return key;
  }
  /**
   * Given an array of layers, return an array of arrays of layers where all
   * layers in each group have identical layout-affecting properties. These
   * are the properties that were formerly used by explicit `ref` mechanism
   * for layers: 'type', 'source', 'source-layer', 'minzoom', 'maxzoom',
   * 'filter', and 'layout'.
   *
   * The input is not modified. The output layers are references to the
   * input layers.
   *
   * @private
   * @param {Array<Layer>} layers
   * @param {Object} [cachedKeys] - an object to keep already calculated keys.
   * @returns {Array<Array<Layer>>}
   */
  function groupByLayout(layers, cachedKeys) {
      const groups = {};
      for (let i = 0; i < layers.length; i++) {
          const k = (cachedKeys && cachedKeys[layers[i].id]) || getKey(layers[i]);
          // update the cache if there is one
          if (cachedKeys)
              cachedKeys[layers[i].id] = k;
          let group = groups[k];
          if (!group) {
              group = groups[k] = [];
          }
          group.push(layers[i]);
      }
      const result = [];
      for (const k in groups) {
          result.push(groups[k]);
      }
      return result;
  }

  function emptyStyle() {
      const style = {};
      const version = v8Spec['$version'];
      for (const styleKey in v8Spec['$root']) {
          const spec = v8Spec['$root'][styleKey];
          if (spec.required) {
              let value = null;
              if (styleKey === 'version') {
                  value = version;
              }
              else {
                  if (spec.type === 'array') {
                      value = [];
                  }
                  else {
                      value = {};
                  }
              }
              if (value != null) {
                  style[styleKey] = value;
              }
          }
      }
      return style;
  }

  function validateConstants(options) {
      const key = options.key;
      const constants = options.value;
      if (constants) {
          return [new ValidationError(key, constants, 'constants have been deprecated as of v8')];
      }
      else {
          return [];
      }
  }

  // Turn jsonlint-lines-primitives objects into primitive objects
  function unbundle(value) {
      if (value instanceof Number || value instanceof String || value instanceof Boolean) {
          return value.valueOf();
      }
      else {
          return value;
      }
  }
  function deepUnbundle(value) {
      if (Array.isArray(value)) {
          return value.map(deepUnbundle);
      }
      else if (value instanceof Object && !(value instanceof Number || value instanceof String || value instanceof Boolean)) {
          const unbundledValue = {};
          for (const key in value) {
              unbundledValue[key] = deepUnbundle(value[key]);
          }
          return unbundledValue;
      }
      return unbundle(value);
  }

  function validateObject(options) {
      const key = options.key;
      const object = options.value;
      const elementSpecs = options.valueSpec || {};
      const elementValidators = options.objectElementValidators || {};
      const style = options.style;
      const styleSpec = options.styleSpec;
      const validateSpec = options.validateSpec;
      let errors = [];
      const type = getType(object);
      if (type !== 'object') {
          return [new ValidationError(key, object, `object expected, ${type} found`)];
      }
      for (const objectKey in object) {
          const elementSpecKey = objectKey.split('.')[0]; // treat 'paint.*' as 'paint'
          const elementSpec = elementSpecs[elementSpecKey] || elementSpecs['*'];
          let validateElement;
          if (elementValidators[elementSpecKey]) {
              validateElement = elementValidators[elementSpecKey];
          }
          else if (elementSpecs[elementSpecKey]) {
              validateElement = validateSpec;
          }
          else if (elementValidators['*']) {
              validateElement = elementValidators['*'];
          }
          else if (elementSpecs['*']) {
              validateElement = validateSpec;
          }
          else {
              errors.push(new ValidationError(key, object[objectKey], `unknown property "${objectKey}"`));
              continue;
          }
          errors = errors.concat(validateElement({
              key: (key ? `${key}.` : key) + objectKey,
              value: object[objectKey],
              valueSpec: elementSpec,
              style,
              styleSpec,
              object,
              objectKey,
              validateSpec,
          }, object));
      }
      for (const elementSpecKey in elementSpecs) {
          // Don't check `required` when there's a custom validator for that property.
          if (elementValidators[elementSpecKey]) {
              continue;
          }
          if (elementSpecs[elementSpecKey].required && elementSpecs[elementSpecKey]['default'] === undefined && object[elementSpecKey] === undefined) {
              errors.push(new ValidationError(key, object, `missing required property "${elementSpecKey}"`));
          }
      }
      return errors;
  }

  function validateArray(options) {
      const array = options.value;
      const arraySpec = options.valueSpec;
      const validateSpec = options.validateSpec;
      const style = options.style;
      const styleSpec = options.styleSpec;
      const key = options.key;
      const validateArrayElement = options.arrayElementValidator || validateSpec;
      if (getType(array) !== 'array') {
          return [new ValidationError(key, array, `array expected, ${getType(array)} found`)];
      }
      if (arraySpec.length && array.length !== arraySpec.length) {
          return [new ValidationError(key, array, `array length ${arraySpec.length} expected, length ${array.length} found`)];
      }
      if (arraySpec['min-length'] && array.length < arraySpec['min-length']) {
          return [new ValidationError(key, array, `array length at least ${arraySpec['min-length']} expected, length ${array.length} found`)];
      }
      let arrayElementSpec = {
          'type': arraySpec.value,
          'values': arraySpec.values
      };
      if (styleSpec.$version < 7) {
          arrayElementSpec['function'] = arraySpec.function;
      }
      if (getType(arraySpec.value) === 'object') {
          arrayElementSpec = arraySpec.value;
      }
      let errors = [];
      for (let i = 0; i < array.length; i++) {
          errors = errors.concat(validateArrayElement({
              array,
              arrayIndex: i,
              value: array[i],
              valueSpec: arrayElementSpec,
              validateSpec: options.validateSpec,
              style,
              styleSpec,
              key: `${key}[${i}]`
          }));
      }
      return errors;
  }

  function validateNumber(options) {
      const key = options.key;
      const value = options.value;
      const valueSpec = options.valueSpec;
      let type = getType(value);
      // eslint-disable-next-line no-self-compare
      if (type === 'number' && value !== value) {
          type = 'NaN';
      }
      if (type !== 'number') {
          return [new ValidationError(key, value, `number expected, ${type} found`)];
      }
      if ('minimum' in valueSpec && value < valueSpec.minimum) {
          return [new ValidationError(key, value, `${value} is less than the minimum value ${valueSpec.minimum}`)];
      }
      if ('maximum' in valueSpec && value > valueSpec.maximum) {
          return [new ValidationError(key, value, `${value} is greater than the maximum value ${valueSpec.maximum}`)];
      }
      return [];
  }

  function validateFunction(options) {
      const functionValueSpec = options.valueSpec;
      const functionType = unbundle(options.value.type);
      let stopKeyType;
      let stopDomainValues = {};
      let previousStopDomainValue;
      let previousStopDomainZoom;
      const isZoomFunction = functionType !== 'categorical' && options.value.property === undefined;
      const isPropertyFunction = !isZoomFunction;
      const isZoomAndPropertyFunction = getType(options.value.stops) === 'array' &&
          getType(options.value.stops[0]) === 'array' &&
          getType(options.value.stops[0][0]) === 'object';
      const errors = validateObject({
          key: options.key,
          value: options.value,
          valueSpec: options.styleSpec.function,
          validateSpec: options.validateSpec,
          style: options.style,
          styleSpec: options.styleSpec,
          objectElementValidators: {
              stops: validateFunctionStops,
              default: validateFunctionDefault
          }
      });
      if (functionType === 'identity' && isZoomFunction) {
          errors.push(new ValidationError(options.key, options.value, 'missing required property "property"'));
      }
      if (functionType !== 'identity' && !options.value.stops) {
          errors.push(new ValidationError(options.key, options.value, 'missing required property "stops"'));
      }
      if (functionType === 'exponential' && options.valueSpec.expression && !supportsInterpolation(options.valueSpec)) {
          errors.push(new ValidationError(options.key, options.value, 'exponential functions not supported'));
      }
      if (options.styleSpec.$version >= 8) {
          if (isPropertyFunction && !supportsPropertyExpression(options.valueSpec)) {
              errors.push(new ValidationError(options.key, options.value, 'property functions not supported'));
          }
          else if (isZoomFunction && !supportsZoomExpression(options.valueSpec)) {
              errors.push(new ValidationError(options.key, options.value, 'zoom functions not supported'));
          }
      }
      if ((functionType === 'categorical' || isZoomAndPropertyFunction) && options.value.property === undefined) {
          errors.push(new ValidationError(options.key, options.value, '"property" property is required'));
      }
      return errors;
      function validateFunctionStops(options) {
          if (functionType === 'identity') {
              return [new ValidationError(options.key, options.value, 'identity function may not have a "stops" property')];
          }
          let errors = [];
          const value = options.value;
          errors = errors.concat(validateArray({
              key: options.key,
              value,
              valueSpec: options.valueSpec,
              validateSpec: options.validateSpec,
              style: options.style,
              styleSpec: options.styleSpec,
              arrayElementValidator: validateFunctionStop
          }));
          if (getType(value) === 'array' && value.length === 0) {
              errors.push(new ValidationError(options.key, value, 'array must have at least one stop'));
          }
          return errors;
      }
      function validateFunctionStop(options) {
          let errors = [];
          const value = options.value;
          const key = options.key;
          if (getType(value) !== 'array') {
              return [new ValidationError(key, value, `array expected, ${getType(value)} found`)];
          }
          if (value.length !== 2) {
              return [new ValidationError(key, value, `array length 2 expected, length ${value.length} found`)];
          }
          if (isZoomAndPropertyFunction) {
              if (getType(value[0]) !== 'object') {
                  return [new ValidationError(key, value, `object expected, ${getType(value[0])} found`)];
              }
              if (value[0].zoom === undefined) {
                  return [new ValidationError(key, value, 'object stop key must have zoom')];
              }
              if (value[0].value === undefined) {
                  return [new ValidationError(key, value, 'object stop key must have value')];
              }
              if (previousStopDomainZoom && previousStopDomainZoom > unbundle(value[0].zoom)) {
                  return [new ValidationError(key, value[0].zoom, 'stop zoom values must appear in ascending order')];
              }
              if (unbundle(value[0].zoom) !== previousStopDomainZoom) {
                  previousStopDomainZoom = unbundle(value[0].zoom);
                  previousStopDomainValue = undefined;
                  stopDomainValues = {};
              }
              errors = errors.concat(validateObject({
                  key: `${key}[0]`,
                  value: value[0],
                  valueSpec: { zoom: {} },
                  validateSpec: options.validateSpec,
                  style: options.style,
                  styleSpec: options.styleSpec,
                  objectElementValidators: { zoom: validateNumber, value: validateStopDomainValue }
              }));
          }
          else {
              errors = errors.concat(validateStopDomainValue({
                  key: `${key}[0]`,
                  value: value[0],
                  valueSpec: {},
                  validateSpec: options.validateSpec,
                  style: options.style,
                  styleSpec: options.styleSpec
              }, value));
          }
          if (isExpression(deepUnbundle(value[1]))) {
              return errors.concat([new ValidationError(`${key}[1]`, value[1], 'expressions are not allowed in function stops.')]);
          }
          return errors.concat(options.validateSpec({
              key: `${key}[1]`,
              value: value[1],
              valueSpec: functionValueSpec,
              validateSpec: options.validateSpec,
              style: options.style,
              styleSpec: options.styleSpec
          }));
      }
      function validateStopDomainValue(options, stop) {
          const type = getType(options.value);
          const value = unbundle(options.value);
          const reportValue = options.value !== null ? options.value : stop;
          if (!stopKeyType) {
              stopKeyType = type;
          }
          else if (type !== stopKeyType) {
              return [new ValidationError(options.key, reportValue, `${type} stop domain type must match previous stop domain type ${stopKeyType}`)];
          }
          if (type !== 'number' && type !== 'string' && type !== 'boolean') {
              return [new ValidationError(options.key, reportValue, 'stop domain value must be a number, string, or boolean')];
          }
          if (type !== 'number' && functionType !== 'categorical') {
              let message = `number expected, ${type} found`;
              if (supportsPropertyExpression(functionValueSpec) && functionType === undefined) {
                  message += '\nIf you intended to use a categorical function, specify `"type": "categorical"`.';
              }
              return [new ValidationError(options.key, reportValue, message)];
          }
          if (functionType === 'categorical' && type === 'number' && (!isFinite(value) || Math.floor(value) !== value)) {
              return [new ValidationError(options.key, reportValue, `integer expected, found ${value}`)];
          }
          if (functionType !== 'categorical' && type === 'number' && previousStopDomainValue !== undefined && value < previousStopDomainValue) {
              return [new ValidationError(options.key, reportValue, 'stop domain values must appear in ascending order')];
          }
          else {
              previousStopDomainValue = value;
          }
          if (functionType === 'categorical' && value in stopDomainValues) {
              return [new ValidationError(options.key, reportValue, 'stop domain values must be unique')];
          }
          else {
              stopDomainValues[value] = true;
          }
          return [];
      }
      function validateFunctionDefault(options) {
          return options.validateSpec({
              key: options.key,
              value: options.value,
              valueSpec: functionValueSpec,
              validateSpec: options.validateSpec,
              style: options.style,
              styleSpec: options.styleSpec
          });
      }
  }

  function validateExpression(options) {
      const expression = (options.expressionContext === 'property' ? createPropertyExpression : createExpression)(deepUnbundle(options.value), options.valueSpec);
      if (expression.result === 'error') {
          return expression.value.map((error) => {
              return new ValidationError(`${options.key}${error.key}`, options.value, error.message);
          });
      }
      const expressionObj = expression.value.expression || expression.value._styleExpression.expression;
      if (options.expressionContext === 'property' && (options.propertyKey === 'text-font') &&
          !expressionObj.outputDefined()) {
          return [new ValidationError(options.key, options.value, `Invalid data expression for "${options.propertyKey}". Output values must be contained as literals within the expression.`)];
      }
      if (options.expressionContext === 'property' && options.propertyType === 'layout' &&
          (!isStateConstant(expressionObj))) {
          return [new ValidationError(options.key, options.value, '"feature-state" data expressions are not supported with layout properties.')];
      }
      if (options.expressionContext === 'filter' && !isStateConstant(expressionObj)) {
          return [new ValidationError(options.key, options.value, '"feature-state" data expressions are not supported with filters.')];
      }
      if (options.expressionContext && options.expressionContext.indexOf('cluster') === 0) {
          if (!isGlobalPropertyConstant(expressionObj, ['zoom', 'feature-state'])) {
              return [new ValidationError(options.key, options.value, '"zoom" and "feature-state" expressions are not supported with cluster properties.')];
          }
          if (options.expressionContext === 'cluster-initial' && !isFeatureConstant(expressionObj)) {
              return [new ValidationError(options.key, options.value, 'Feature data expressions are not supported with initial expression part of cluster properties.')];
          }
      }
      return [];
  }

  function validateBoolean(options) {
      const value = options.value;
      const key = options.key;
      const type = getType(value);
      if (type !== 'boolean') {
          return [new ValidationError(key, value, `boolean expected, ${type} found`)];
      }
      return [];
  }

  function validateColor(options) {
      const key = options.key;
      const value = options.value;
      const type = getType(value);
      if (type !== 'string') {
          return [new ValidationError(key, value, `color expected, ${type} found`)];
      }
      if (!Color.parse(String(value))) { // cast String object to string primitive
          return [new ValidationError(key, value, `color expected, "${value}" found`)];
      }
      return [];
  }

  function validateEnum(options) {
      const key = options.key;
      const value = options.value;
      const valueSpec = options.valueSpec;
      const errors = [];
      if (Array.isArray(valueSpec.values)) { // <=v7
          if (valueSpec.values.indexOf(unbundle(value)) === -1) {
              errors.push(new ValidationError(key, value, `expected one of [${valueSpec.values.join(', ')}], ${JSON.stringify(value)} found`));
          }
      }
      else { // >=v8
          if (Object.keys(valueSpec.values).indexOf(unbundle(value)) === -1) {
              errors.push(new ValidationError(key, value, `expected one of [${Object.keys(valueSpec.values).join(', ')}], ${JSON.stringify(value)} found`));
          }
      }
      return errors;
  }

  function validateFilter(options) {
      if (isExpressionFilter(deepUnbundle(options.value))) {
          return validateExpression(extendBy({}, options, {
              expressionContext: 'filter',
              valueSpec: { value: 'boolean' }
          }));
      }
      else {
          return validateNonExpressionFilter(options);
      }
  }
  function validateNonExpressionFilter(options) {
      const value = options.value;
      const key = options.key;
      if (getType(value) !== 'array') {
          return [new ValidationError(key, value, `array expected, ${getType(value)} found`)];
      }
      const styleSpec = options.styleSpec;
      let type;
      let errors = [];
      if (value.length < 1) {
          return [new ValidationError(key, value, 'filter array must have at least 1 element')];
      }
      errors = errors.concat(validateEnum({
          key: `${key}[0]`,
          value: value[0],
          valueSpec: styleSpec.filter_operator,
          style: options.style,
          styleSpec: options.styleSpec
      }));
      switch (unbundle(value[0])) {
          case '<':
          case '<=':
          case '>':
          case '>=':
              if (value.length >= 2 && unbundle(value[1]) === '$type') {
                  errors.push(new ValidationError(key, value, `"$type" cannot be use with operator "${value[0]}"`));
              }
          /* falls through */
          case '==':
          case '!=':
              if (value.length !== 3) {
                  errors.push(new ValidationError(key, value, `filter array for operator "${value[0]}" must have 3 elements`));
              }
          /* falls through */
          case 'in':
          case '!in':
              if (value.length >= 2) {
                  type = getType(value[1]);
                  if (type !== 'string') {
                      errors.push(new ValidationError(`${key}[1]`, value[1], `string expected, ${type} found`));
                  }
              }
              for (let i = 2; i < value.length; i++) {
                  type = getType(value[i]);
                  if (unbundle(value[1]) === '$type') {
                      errors = errors.concat(validateEnum({
                          key: `${key}[${i}]`,
                          value: value[i],
                          valueSpec: styleSpec.geometry_type,
                          style: options.style,
                          styleSpec: options.styleSpec
                      }));
                  }
                  else if (type !== 'string' && type !== 'number' && type !== 'boolean') {
                      errors.push(new ValidationError(`${key}[${i}]`, value[i], `string, number, or boolean expected, ${type} found`));
                  }
              }
              break;
          case 'any':
          case 'all':
          case 'none':
              for (let i = 1; i < value.length; i++) {
                  errors = errors.concat(validateNonExpressionFilter({
                      key: `${key}[${i}]`,
                      value: value[i],
                      style: options.style,
                      styleSpec: options.styleSpec
                  }));
              }
              break;
          case 'has':
          case '!has':
              type = getType(value[1]);
              if (value.length !== 2) {
                  errors.push(new ValidationError(key, value, `filter array for "${value[0]}" operator must have 2 elements`));
              }
              else if (type !== 'string') {
                  errors.push(new ValidationError(`${key}[1]`, value[1], `string expected, ${type} found`));
              }
              break;
          case 'within':
              type = getType(value[1]);
              if (value.length !== 2) {
                  errors.push(new ValidationError(key, value, `filter array for "${value[0]}" operator must have 2 elements`));
              }
              else if (type !== 'object') {
                  errors.push(new ValidationError(`${key}[1]`, value[1], `object expected, ${type} found`));
              }
              break;
      }
      return errors;
  }

  function validateProperty(options, propertyType) {
      const key = options.key;
      const validateSpec = options.validateSpec;
      const style = options.style;
      const styleSpec = options.styleSpec;
      const value = options.value;
      const propertyKey = options.objectKey;
      const layerSpec = styleSpec[`${propertyType}_${options.layerType}`];
      if (!layerSpec)
          return [];
      const transitionMatch = propertyKey.match(/^(.*)-transition$/);
      if (propertyType === 'paint' && transitionMatch && layerSpec[transitionMatch[1]] && layerSpec[transitionMatch[1]].transition) {
          return validateSpec({
              key,
              value,
              valueSpec: styleSpec.transition,
              style,
              styleSpec
          });
      }
      const valueSpec = options.valueSpec || layerSpec[propertyKey];
      if (!valueSpec) {
          return [new ValidationError(key, value, `unknown property "${propertyKey}"`)];
      }
      let tokenMatch;
      if (getType(value) === 'string' && supportsPropertyExpression(valueSpec) && !valueSpec.tokens && (tokenMatch = /^{([^}]+)}$/.exec(value))) {
          return [new ValidationError(key, value, `"${propertyKey}" does not support interpolation syntax\n` +
                  `Use an identity property function instead: \`{ "type": "identity", "property": ${JSON.stringify(tokenMatch[1])} }\`.`)];
      }
      const errors = [];
      if (options.layerType === 'symbol') {
          if (propertyKey === 'text-field' && style && !style.glyphs) {
              errors.push(new ValidationError(key, value, 'use of "text-field" requires a style "glyphs" property'));
          }
          if (propertyKey === 'text-font' && isFunction(deepUnbundle(value)) && unbundle(value.type) === 'identity') {
              errors.push(new ValidationError(key, value, '"text-font" does not support identity functions'));
          }
      }
      return errors.concat(validateSpec({
          key: options.key,
          value,
          valueSpec,
          style,
          styleSpec,
          expressionContext: 'property',
          propertyType,
          propertyKey
      }));
  }

  function validatePaintProperty(options) {
      return validateProperty(options, 'paint');
  }

  function validateLayoutProperty(options) {
      return validateProperty(options, 'layout');
  }

  function validateLayer(options) {
      let errors = [];
      const layer = options.value;
      const key = options.key;
      const style = options.style;
      const styleSpec = options.styleSpec;
      if (!layer.type && !layer.ref) {
          errors.push(new ValidationError(key, layer, 'either "type" or "ref" is required'));
      }
      let type = unbundle(layer.type);
      const ref = unbundle(layer.ref);
      if (layer.id) {
          const layerId = unbundle(layer.id);
          for (let i = 0; i < options.arrayIndex; i++) {
              const otherLayer = style.layers[i];
              if (unbundle(otherLayer.id) === layerId) {
                  errors.push(new ValidationError(key, layer.id, `duplicate layer id "${layer.id}", previously used at line ${otherLayer.id.__line__}`));
              }
          }
      }
      if ('ref' in layer) {
          ['type', 'source', 'source-layer', 'filter', 'layout'].forEach((p) => {
              if (p in layer) {
                  errors.push(new ValidationError(key, layer[p], `"${p}" is prohibited for ref layers`));
              }
          });
          let parent;
          style.layers.forEach((layer) => {
              if (unbundle(layer.id) === ref)
                  parent = layer;
          });
          if (!parent) {
              errors.push(new ValidationError(key, layer.ref, `ref layer "${ref}" not found`));
          }
          else if (parent.ref) {
              errors.push(new ValidationError(key, layer.ref, 'ref cannot reference another ref layer'));
          }
          else {
              type = unbundle(parent.type);
          }
      }
      else if (type !== 'background') {
          if (!layer.source) {
              errors.push(new ValidationError(key, layer, 'missing required property "source"'));
          }
          else {
              const source = style.sources && style.sources[layer.source];
              const sourceType = source && unbundle(source.type);
              if (!source) {
                  errors.push(new ValidationError(key, layer.source, `source "${layer.source}" not found`));
              }
              else if (sourceType === 'vector' && type === 'raster') {
                  errors.push(new ValidationError(key, layer.source, `layer "${layer.id}" requires a raster source`));
              }
              else if (sourceType === 'raster' && type !== 'raster') {
                  errors.push(new ValidationError(key, layer.source, `layer "${layer.id}" requires a vector source`));
              }
              else if (sourceType === 'vector' && !layer['source-layer']) {
                  errors.push(new ValidationError(key, layer, `layer "${layer.id}" must specify a "source-layer"`));
              }
              else if (sourceType === 'raster-dem' && type !== 'hillshade' && type !== 'colorramp') {
                  errors.push(new ValidationError(key, layer.source, 'raster-dem source can only be used with layer type \'hillshade\' or \'colorramp\'.'));
              }
              else if (type === 'line' && layer.paint && layer.paint['line-gradient'] &&
                  (sourceType !== 'geojson' || !source.lineMetrics)) {
                  errors.push(new ValidationError(key, layer, `layer "${layer.id}" specifies a line-gradient, which requires a GeoJSON source with \`lineMetrics\` enabled.`));
              }
          }
      }
      errors = errors.concat(validateObject({
          key,
          value: layer,
          valueSpec: styleSpec.layer,
          style: options.style,
          styleSpec: options.styleSpec,
          validateSpec: options.validateSpec,
          objectElementValidators: {
              '*'() {
                  return [];
              },
              // We don't want to enforce the spec's `"requires": true` for backward compatibility with refs;
              // the actual requirement is validated above. See https://github.com/mapbox/mapbox-gl-js/issues/5772.
              type() {
                  return options.validateSpec({
                      key: `${key}.type`,
                      value: layer.type,
                      valueSpec: styleSpec.layer.type,
                      style: options.style,
                      styleSpec: options.styleSpec,
                      validateSpec: options.validateSpec,
                      object: layer,
                      objectKey: 'type'
                  });
              },
              filter: validateFilter,
              layout(options) {
                  return validateObject({
                      layer,
                      key: options.key,
                      value: options.value,
                      style: options.style,
                      styleSpec: options.styleSpec,
                      validateSpec: options.validateSpec,
                      objectElementValidators: {
                          '*'(options) {
                              return validateLayoutProperty(extendBy({ layerType: type }, options));
                          }
                      }
                  });
              },
              paint(options) {
                  return validateObject({
                      layer,
                      key: options.key,
                      value: options.value,
                      style: options.style,
                      styleSpec: options.styleSpec,
                      validateSpec: options.validateSpec,
                      objectElementValidators: {
                          '*'(options) {
                              return validatePaintProperty(extendBy({ layerType: type }, options));
                          }
                      }
                  });
              }
          }
      }));
      return errors;
  }

  function validateString(options) {
      const value = options.value;
      const key = options.key;
      const type = getType(value);
      if (type !== 'string') {
          return [new ValidationError(key, value, `string expected, ${type} found`)];
      }
      return [];
  }

  const objectElementValidators = {
      promoteId: validatePromoteId
  };
  function validateSource(options) {
      const value = options.value;
      const key = options.key;
      const styleSpec = options.styleSpec;
      const style = options.style;
      const validateSpec = options.validateSpec;
      if (!value.type) {
          return [new ValidationError(key, value, '"type" is required')];
      }
      const type = unbundle(value.type);
      let errors;
      switch (type) {
          case 'vector':
          case 'raster':
          case 'raster-dem':
              errors = validateObject({
                  key,
                  value,
                  valueSpec: styleSpec[`source_${type.replace('-', '_')}`],
                  style: options.style,
                  styleSpec,
                  objectElementValidators,
                  validateSpec,
              });
              return errors;
          case 'geojson':
              errors = validateObject({
                  key,
                  value,
                  valueSpec: styleSpec.source_geojson,
                  style,
                  styleSpec,
                  validateSpec,
                  objectElementValidators
              });
              if (value.cluster) {
                  for (const prop in value.clusterProperties) {
                      const [operator, mapExpr] = value.clusterProperties[prop];
                      const reduceExpr = typeof operator === 'string' ? [operator, ['accumulated'], ['get', prop]] : operator;
                      errors.push(...validateExpression({
                          key: `${key}.${prop}.map`,
                          value: mapExpr,
                          validateSpec,
                          expressionContext: 'cluster-map'
                      }));
                      errors.push(...validateExpression({
                          key: `${key}.${prop}.reduce`,
                          value: reduceExpr,
                          validateSpec,
                          expressionContext: 'cluster-reduce'
                      }));
                  }
              }
              return errors;
          case 'video':
              return validateObject({
                  key,
                  value,
                  valueSpec: styleSpec.source_video,
                  style,
                  validateSpec,
                  styleSpec
              });
          case 'image':
              return validateObject({
                  key,
                  value,
                  valueSpec: styleSpec.source_image,
                  style,
                  validateSpec,
                  styleSpec
              });
          case 'canvas':
              return [new ValidationError(key, null, 'Please use runtime APIs to add canvas sources, rather than including them in stylesheets.', 'source.canvas')];
          default:
              return validateEnum({
                  key: `${key}.type`,
                  value: value.type,
                  valueSpec: { values: ['vector', 'raster', 'raster-dem', 'geojson', 'video', 'image'] },
                  style,
                  validateSpec,
                  styleSpec
              });
      }
  }
  function validatePromoteId({ key, value }) {
      if (getType(value) === 'string') {
          return validateString({ key, value });
      }
      else {
          const errors = [];
          for (const prop in value) {
              errors.push(...validateString({ key: `${key}.${prop}`, value: value[prop] }));
          }
          return errors;
      }
  }

  function validateLight(options) {
      const light = options.value;
      const styleSpec = options.styleSpec;
      const lightSpec = styleSpec.light;
      const style = options.style;
      let errors = [];
      const rootType = getType(light);
      if (light === undefined) {
          return errors;
      }
      else if (rootType !== 'object') {
          errors = errors.concat([new ValidationError('light', light, `object expected, ${rootType} found`)]);
          return errors;
      }
      for (const key in light) {
          const transitionMatch = key.match(/^(.*)-transition$/);
          if (transitionMatch && lightSpec[transitionMatch[1]] && lightSpec[transitionMatch[1]].transition) {
              errors = errors.concat(options.validateSpec({
                  key,
                  value: light[key],
                  valueSpec: styleSpec.transition,
                  validateSpec: options.validateSpec,
                  style,
                  styleSpec
              }));
          }
          else if (lightSpec[key]) {
              errors = errors.concat(options.validateSpec({
                  key,
                  value: light[key],
                  valueSpec: lightSpec[key],
                  validateSpec: options.validateSpec,
                  style,
                  styleSpec
              }));
          }
          else {
              errors = errors.concat([new ValidationError(key, light[key], `unknown property "${key}"`)]);
          }
      }
      return errors;
  }

  function validateTerrain(options) {
      const terrain = options.value;
      const styleSpec = options.styleSpec;
      const terrainSpec = styleSpec.terrain;
      const style = options.style;
      let errors = [];
      const rootType = getType(terrain);
      if (terrain === undefined) {
          return errors;
      }
      else if (rootType !== 'object') {
          errors = errors.concat([new ValidationError('terrain', terrain, `object expected, ${rootType} found`)]);
          return errors;
      }
      for (const key in terrain) {
          if (terrainSpec[key]) {
              errors = errors.concat(options.validateSpec({
                  key,
                  value: terrain[key],
                  valueSpec: terrainSpec[key],
                  validateSpec: options.validateSpec,
                  style,
                  styleSpec
              }));
          }
          else {
              errors = errors.concat([new ValidationError(key, terrain[key], `unknown property "${key}"`)]);
          }
      }
      return errors;
  }

  function validateFormatted(options) {
      if (validateString(options).length === 0) {
          return [];
      }
      return validateExpression(options);
  }

  function validateImage(options) {
      if (validateString(options).length === 0) {
          return [];
      }
      return validateExpression(options);
  }

  function validatePadding(options) {
      const key = options.key;
      const value = options.value;
      const type = getType(value);
      if (type === 'array') {
          if (value.length < 1 || value.length > 4) {
              return [new ValidationError(key, value, `padding requires 1 to 4 values; ${value.length} values found`)];
          }
          const arrayElementSpec = {
              type: 'number'
          };
          let errors = [];
          for (let i = 0; i < value.length; i++) {
              errors = errors.concat(options.validateSpec({
                  key: `${key}[${i}]`,
                  value: value[i],
                  validateSpec: options.validateSpec,
                  valueSpec: arrayElementSpec
              }));
          }
          return errors;
      }
      else {
          return validateNumber({
              key,
              value,
              valueSpec: {}
          });
      }
  }

  function validateVariableAnchorOffsetCollection(options) {
      const key = options.key;
      const value = options.value;
      const type = getType(value);
      const styleSpec = options.styleSpec;
      if (type !== 'array' || value.length < 1 || value.length % 2 !== 0) {
          return [new ValidationError(key, value, 'variableAnchorOffsetCollection requires a non-empty array of even length')];
      }
      let errors = [];
      for (let i = 0; i < value.length; i += 2) {
          // Elements in even positions should be values from text-anchor enum
          errors = errors.concat(validateEnum({
              key: `${key}[${i}]`,
              value: value[i],
              valueSpec: styleSpec['layout_symbol']['text-anchor']
          }));
          // Elements in odd positions should be points (2-element numeric arrays)
          errors = errors.concat(validateArray({
              key: `${key}[${i + 1}]`,
              value: value[i + 1],
              valueSpec: {
                  length: 2,
                  value: 'number'
              },
              validateSpec: options.validateSpec,
              style: options.style,
              styleSpec
          }));
      }
      return errors;
  }

  function validateSprite(options) {
      let errors = [];
      const sprite = options.value;
      const key = options.key;
      if (!Array.isArray(sprite)) {
          return validateString({
              key,
              value: sprite
          });
      }
      else {
          const allSpriteIds = [];
          const allSpriteURLs = [];
          for (const i in sprite) {
              if (sprite[i].id && allSpriteIds.includes(sprite[i].id))
                  errors.push(new ValidationError(key, sprite, `all the sprites' ids must be unique, but ${sprite[i].id} is duplicated`));
              allSpriteIds.push(sprite[i].id);
              if (sprite[i].url && allSpriteURLs.includes(sprite[i].url))
                  errors.push(new ValidationError(key, sprite, `all the sprites' URLs must be unique, but ${sprite[i].url} is duplicated`));
              allSpriteURLs.push(sprite[i].url);
              const pairSpec = {
                  id: {
                      type: 'string',
                      required: true,
                  },
                  url: {
                      type: 'string',
                      required: true,
                  }
              };
              errors = errors.concat(validateObject({
                  key: `${key}[${i}]`,
                  value: sprite[i],
                  valueSpec: pairSpec,
                  validateSpec: options.validateSpec,
              }));
          }
          return errors;
      }
  }

  const VALIDATORS = {
      '*'() {
          return [];
      },
      'array': validateArray,
      'boolean': validateBoolean,
      'number': validateNumber,
      'color': validateColor,
      'constants': validateConstants,
      'enum': validateEnum,
      'filter': validateFilter,
      'function': validateFunction,
      'layer': validateLayer,
      'object': validateObject,
      'source': validateSource,
      'light': validateLight,
      'terrain': validateTerrain,
      'string': validateString,
      'formatted': validateFormatted,
      'resolvedImage': validateImage,
      'padding': validatePadding,
      'variableAnchorOffsetCollection': validateVariableAnchorOffsetCollection,
      'sprite': validateSprite,
  };
  // Main recursive validation function. Tracks:
  //
  // - key: string representing location of validation in style tree. Used only
  //   for more informative error reporting.
  // - value: current value from style being evaluated. May be anything from a
  //   high level object that needs to be descended into deeper or a simple
  //   scalar value.
  // - valueSpec: current spec being evaluated. Tracks value.
  // - styleSpec: current full spec being evaluated.
  function validate(options) {
      const value = options.value;
      const valueSpec = options.valueSpec;
      const styleSpec = options.styleSpec;
      options.validateSpec = validate;
      if (valueSpec.expression && isFunction(unbundle(value))) {
          return validateFunction(options);
      }
      else if (valueSpec.expression && isExpression(deepUnbundle(value))) {
          return validateExpression(options);
      }
      else if (valueSpec.type && VALIDATORS[valueSpec.type]) {
          return VALIDATORS[valueSpec.type](options);
      }
      else {
          const valid = validateObject(extendBy({}, options, {
              valueSpec: valueSpec.type ? styleSpec[valueSpec.type] : valueSpec
          }));
          return valid;
      }
  }

  function validateGlyphsUrl(options) {
      const value = options.value;
      const key = options.key;
      const errors = validateString(options);
      if (errors.length)
          return errors;
      if (value.indexOf('{fontstack}') === -1) {
          errors.push(new ValidationError(key, value, '"glyphs" url must include a "{fontstack}" token'));
      }
      if (value.indexOf('{range}') === -1) {
          errors.push(new ValidationError(key, value, '"glyphs" url must include a "{range}" token'));
      }
      return errors;
  }

  /**
   * Validate a MapLibre style against the style specification. This entrypoint,
   * `maplibre-gl-style-spec/lib/validate_style.min`, is designed to produce as
   * small a browserify bundle as possible by omitting unnecessary functionality
   * and legacy style specifications.
   *
   * @private
   * @param {Object} style The style to be validated.
   * @param {Object} [styleSpec] The style specification to validate against.
   *     If omitted, the latest style spec is used.
   * @returns {Array<ValidationError>}
   * @example
   *   var validate = require('maplibre-gl-style-spec/lib/validate_style.min');
   *   var errors = validate(style);
   */
  function validateStyleMin(style, styleSpec = v8Spec) {
      let errors = [];
      errors = errors.concat(validate({
          key: '',
          value: style,
          valueSpec: styleSpec.$root,
          styleSpec,
          style,
          validateSpec: validate,
          objectElementValidators: {
              glyphs: validateGlyphsUrl,
              '*'() {
                  return [];
              }
          }
      }));
      if (style['constants']) {
          errors = errors.concat(validateConstants({
              key: 'constants',
              value: style['constants'],
              style,
              styleSpec,
              validateSpec: validate,
          }));
      }
      return sortErrors(errors);
  }
  validateStyleMin.source = wrapCleanErrors(injectValidateSpec(validateSource));
  validateStyleMin.sprite = wrapCleanErrors(injectValidateSpec(validateSprite));
  validateStyleMin.glyphs = wrapCleanErrors(injectValidateSpec(validateGlyphsUrl));
  validateStyleMin.light = wrapCleanErrors(injectValidateSpec(validateLight));
  validateStyleMin.terrain = wrapCleanErrors(injectValidateSpec(validateTerrain));
  validateStyleMin.layer = wrapCleanErrors(injectValidateSpec(validateLayer));
  validateStyleMin.filter = wrapCleanErrors(injectValidateSpec(validateFilter));
  validateStyleMin.paintProperty = wrapCleanErrors(injectValidateSpec(validatePaintProperty));
  validateStyleMin.layoutProperty = wrapCleanErrors(injectValidateSpec(validateLayoutProperty));
  function injectValidateSpec(validator) {
      return function (options) {
          return validator({
              ...options,
              validateSpec: validate,
          });
      };
  }
  function sortErrors(errors) {
      return [].concat(errors).sort((a, b) => {
          return a.line - b.line;
      });
  }
  function wrapCleanErrors(inner) {
      return function (...args) {
          return sortErrors(inner.apply(this, args));
      };
  }

  const v8 = v8Spec;
  const expression = {
      StyleExpression,
      StylePropertyFunction,
      ZoomConstantExpression,
      ZoomDependentExpression,
      createExpression,
      createPropertyExpression,
      isExpression,
      isExpressionFilter,
      isZoomExpression,
      normalizePropertyExpression,
  };
  const styleFunction = {
      convertFunction,
      createFunction,
      isFunction
  };
  const visit = { eachLayer, eachProperty, eachSource };

  exports.Color = Color;
  exports.ColorType = ColorType;
  exports.CompoundExpression = CompoundExpression;
  exports.EvaluationContext = EvaluationContext;
  exports.FormatExpression = FormatExpression;
  exports.Formatted = Formatted;
  exports.FormattedSection = FormattedSection;
  exports.FormattedType = FormattedType;
  exports.Interpolate = Interpolate;
  exports.Literal = Literal;
  exports.NullType = NullType;
  exports.Padding = Padding;
  exports.ParsingError = ParsingError;
  exports.ResolvedImage = ResolvedImage;
  exports.Step = Step;
  exports.StyleExpression = StyleExpression;
  exports.StylePropertyFunction = StylePropertyFunction;
  exports.ValidationError = ValidationError;
  exports.VariableAnchorOffsetCollection = VariableAnchorOffsetCollection;
  exports.ZoomConstantExpression = ZoomConstantExpression;
  exports.ZoomDependentExpression = ZoomDependentExpression;
  exports.convertFilter = convertFilter;
  exports.convertFunction = convertFunction;
  exports.createExpression = createExpression;
  exports.createFunction = createFunction;
  exports.createPropertyExpression = createPropertyExpression;
  exports.derefLayers = derefLayers;
  exports.diff = diffStyles;
  exports.emptyStyle = emptyStyle;
  exports.expression = expression;
  exports.expressions = expressions;
  exports.featureFilter = createFilter;
  exports.function = styleFunction;
  exports.groupByLayout = groupByLayout;
  exports.interpolateFactory = interpolateFactory;
  exports.interpolates = interpolate;
  exports.isExpression = isExpression;
  exports.isFunction = isFunction;
  exports.isZoomExpression = isZoomExpression;
  exports.latest = v8Spec;
  exports.normalizePropertyExpression = normalizePropertyExpression;
  exports.operations = operations;
  exports.supportsPropertyExpression = supportsPropertyExpression;
  exports.toString = toString$1;
  exports.typeOf = typeOf;
  exports.v8 = v8;
  exports.validateStyleMin = validateStyleMin;
  exports.visit = visit;

}));
//# sourceMappingURL=index.cjs.map