mathjs/src/expression/node/ObjectNode.js

'use strict'

const stringify = require('../../utils/string').stringify
const escape = require('../../utils/string').escape
const isSafeProperty = require('../../utils/customs').isSafeProperty
const hasOwnProperty = require('../../utils/object').hasOwnProperty

function factory (type, config, load, typed) {
  const Node = load(require('./Node'))

  /**
   * @constructor ObjectNode
   * @extends {Node}
   * Holds an object with keys/values
   * @param {Object.<string, Node>} [properties]   object with key/value pairs
   */
  function ObjectNode (properties) {
    if (!(this instanceof ObjectNode)) {
      throw new SyntaxError('Constructor must be called with the new operator')
    }

    this.properties = properties || {}

    // validate input
    if (properties) {
      if (!(typeof properties === 'object') || !Object.keys(properties).every(function (key) {
        return type.isNode(properties[key])
      })) {
        throw new TypeError('Object containing Nodes expected')
      }
    }
  }

  ObjectNode.prototype = new Node()

  ObjectNode.prototype.type = 'ObjectNode'

  ObjectNode.prototype.isObjectNode = true

  /**
   * Compile a node into a JavaScript function.
   * This basically pre-calculates as much as possible and only leaves open
   * calculations which depend on a dynamic scope with variables.
   * @param {Object} math     Math.js namespace with functions and constants.
   * @param {Object} argNames An object with argument names as key and `true`
   *                          as value. Used in the SymbolNode to optimize
   *                          for arguments from user assigned functions
   *                          (see FunctionAssignmentNode) or special symbols
   *                          like `end` (see IndexNode).
   * @return {function} Returns a function which can be called like:
   *                        evalNode(scope: Object, args: Object, context: *)
   */
  ObjectNode.prototype._compile = function (math, argNames) {
    const evalEntries = {}

    for (const key in this.properties) {
      if (hasOwnProperty(this.properties, key)) {
        // we stringify/parse the key here to resolve unicode characters,
        // so you cannot create a key like {"co\\u006Estructor": null}
        const stringifiedKey = stringify(key)
        const parsedKey = JSON.parse(stringifiedKey)
        if (!isSafeProperty(this.properties, parsedKey)) {
          throw new Error('No access to property "' + parsedKey + '"')
        }

        evalEntries[parsedKey] = this.properties[key]._compile(math, argNames)
      }
    }

    return function evalObjectNode (scope, args, context) {
      const obj = {}

      for (const key in evalEntries) {
        if (hasOwnProperty(evalEntries, key)) {
          obj[key] = evalEntries[key](scope, args, context)
        }
      }

      return obj
    }
  }

  /**
   * Execute a callback for each of the child nodes of this node
   * @param {function(child: Node, path: string, parent: Node)} callback
   */
  ObjectNode.prototype.forEach = function (callback) {
    for (const key in this.properties) {
      if (this.properties.hasOwnProperty(key)) {
        callback(this.properties[key], 'properties[' + stringify(key) + ']', this)
      }
    }
  }

  /**
   * Create a new ObjectNode having it's childs be the results of calling
   * the provided callback function for each of the childs of the original node.
   * @param {function(child: Node, path: string, parent: Node): Node} callback
   * @returns {ObjectNode} Returns a transformed copy of the node
   */
  ObjectNode.prototype.map = function (callback) {
    const properties = {}
    for (const key in this.properties) {
      if (this.properties.hasOwnProperty(key)) {
        properties[key] = this._ifNode(callback(this.properties[key],
          'properties[' + stringify(key) + ']', this))
      }
    }
    return new ObjectNode(properties)
  }

  /**
   * Create a clone of this node, a shallow copy
   * @return {ObjectNode}
   */
  ObjectNode.prototype.clone = function () {
    const properties = {}
    for (const key in this.properties) {
      if (this.properties.hasOwnProperty(key)) {
        properties[key] = this.properties[key]
      }
    }
    return new ObjectNode(properties)
  }

  /**
   * Get string representation
   * @param {Object} options
   * @return {string} str
   * @override
   */
  ObjectNode.prototype._toString = function (options) {
    const entries = []
    for (const key in this.properties) {
      if (this.properties.hasOwnProperty(key)) {
        entries.push(stringify(key) + ': ' + this.properties[key].toString(options))
      }
    }
    return '{' + entries.join(', ') + '}'
  }

  /**
   * Get a JSON representation of the node
   * @returns {Object}
   */
  ObjectNode.prototype.toJSON = function () {
    return {
      mathjs: 'ObjectNode',
      properties: this.properties
    }
  }

  /**
   * Instantiate an OperatorNode from its JSON representation
   * @param {Object} json  An object structured like
   *                       `{"mathjs": "ObjectNode", "properties": {...}}`,
   *                       where mathjs is optional
   * @returns {ObjectNode}
   */
  ObjectNode.fromJSON = function (json) {
    return new ObjectNode(json.properties)
  }

  /**
   * Get HTML representation
   * @param {Object} options
   * @return {string} str
   * @override
   */
  ObjectNode.prototype.toHTML = function (options) {
    const entries = []
    for (const key in this.properties) {
      if (this.properties.hasOwnProperty(key)) {
        entries.push('<span class="math-symbol math-property">' + escape(key) + '</span>' + '<span class="math-operator math-assignment-operator math-property-assignment-operator math-binary-operator">:</span>' + this.properties[key].toHTML(options))
      }
    }
    return '<span class="math-parenthesis math-curly-parenthesis">{</span>' + entries.join('<span class="math-separator">,</span>') + '<span class="math-parenthesis math-curly-parenthesis">}</span>'
  }

  /**
   * Get LaTeX representation
   * @param {Object} options
   * @return {string} str
   */
  ObjectNode.prototype._toTex = function (options) {
    const entries = []
    for (const key in this.properties) {
      if (this.properties.hasOwnProperty(key)) {
        entries.push('\\mathbf{' + key + ':} & ' + this.properties[key].toTex(options) + '\\\\')
      }
    }
    return `\\left\\{\\begin{array}{ll}${entries.join('\n')}\\end{array}\\right\\}`
  }

  return ObjectNode
}

exports.name = 'ObjectNode'
exports.path = 'expression.node'
exports.factory = factory