eslint-plugin-babel/rules/object-curly-spacing.js

/**
 * @fileoverview Disallows or enforces spaces inside of object literals.
 * @author Jamund Ferguson
 * @copyright 2014 Brandyn Bennett. All rights reserved.
 * @copyright 2014 Michael Ficarra. No rights reserved.
 * @copyright 2014 Vignesh Anand. All rights reserved.
 * @copyright 2015 Jamund Ferguson. All rights reserved.
 * @copyright 2015 Mathieu M-Gosselin. All rights reserved.
 * @copyright 2015 Toru Nagashima. All rights reserved.
 * See LICENSE file in root directory for full license.
 */
"use strict";

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

module.exports = function(context) {
    var spaced = context.options[0] === "always",
        sourceCode = context.getSourceCode();

    /**
     * Determines whether an option is set, relative to the spacing option.
     * If spaced is "always", then check whether option is set to false.
     * If spaced is "never", then check whether option is set to true.
     * @param {Object} option - The option to exclude.
     * @returns {boolean} Whether or not the property is excluded.
     */
    function isOptionSet(option) {
        return context.options[1] != null ? context.options[1][option] === !spaced : false;
    }

    var options = {
        spaced: spaced,
        arraysInObjectsException: isOptionSet("arraysInObjects"),
        objectsInObjectsException: isOptionSet("objectsInObjects")
    };

    //--------------------------------------------------------------------------
    // Helpers
    //--------------------------------------------------------------------------

    /**
     * Determines whether two adjacent tokens are have whitespace between them.
     * @param {Object} left - The left token object.
     * @param {Object} right - The right token object.
     * @returns {boolean} Whether or not there is space between the tokens.
     */
    function isSpaced(left, right) {
        return sourceCode.isSpaceBetweenTokens(left, right);
    }

    /**
     * Determines whether two adjacent tokens are on the same line.
     * @param {Object} left - The left token object.
     * @param {Object} right - The right token object.
     * @returns {boolean} Whether or not the tokens are on the same line.
     */
    function isSameLine(left, right) {
        return left.loc.start.line === right.loc.start.line;
    }

    /**
    * Reports that there shouldn't be a space after the first token
    * @param {ASTNode} node - The node to report in the event of an error.
    * @param {Token} token - The token to use for the report.
    * @returns {void}
    */
    function reportNoBeginningSpace(node, token) {
        context.report({
            node: node,
            loc: token.loc.end,
            message: "There should be no space after '" + token.value + "'",
            fix: function(fixer) {
                var nextToken = sourceCode.getTokenAfter(token);
                return fixer.removeRange([token.range[1], nextToken.range[0]]);
            }
        });
    }

    /**
    * Reports that there shouldn't be a space before the last token
    * @param {ASTNode} node - The node to report in the event of an error.
    * @param {Token} token - The token to use for the report.
    * @returns {void}
    */
    function reportNoEndingSpace(node, token) {
        context.report({
            node: node,
            loc: token.loc.start,
            message: "There should be no space before '" + token.value + "'",
            fix: function(fixer) {
                var previousToken = sourceCode.getTokenBefore(token);
                return fixer.removeRange([previousToken.range[1], token.range[0]]);
            }
        });
    }

    /**
    * Reports that there should be a space after the first token
    * @param {ASTNode} node - The node to report in the event of an error.
    * @param {Token} token - The token to use for the report.
    * @returns {void}
    */
    function reportRequiredBeginningSpace(node, token) {
        context.report({
            node: node,
            loc: token.loc.end,
            message: "A space is required after '" + token.value + "'",
            fix: function(fixer) {
                return fixer.insertTextAfter(token, " ");
            }
        });
    }

    /**
    * Reports that there should be a space before the last token
    * @param {ASTNode} node - The node to report in the event of an error.
    * @param {Token} token - The token to use for the report.
    * @returns {void}
    */
    function reportRequiredEndingSpace(node, token) {
        context.report({
            node: node,
            loc: token.loc.start,
            message: "A space is required before '" + token.value + "'",
            fix: function(fixer) {
                return fixer.insertTextBefore(token, " ");
            }
        });
    }

    /**
     * Determines if spacing in curly braces is valid.
     * @param {ASTNode} node The AST node to check.
     * @param {Token} first The first token to check (should be the opening brace)
     * @param {Token} second The second token to check (should be first after the opening brace)
     * @param {Token} penultimate The penultimate token to check (should be last before closing brace)
     * @param {Token} last The last token to check (should be closing brace)
     * @returns {void}
     */
    function validateBraceSpacing(node, first, second, penultimate, last) {
        var closingCurlyBraceMustBeSpaced =
            options.arraysInObjectsException && penultimate.value === "]" ||
            options.objectsInObjectsException && penultimate.value === "}"
                ? !options.spaced : options.spaced;

        if (isSameLine(first, second)) {
            if (options.spaced && !isSpaced(first, second)) {
                reportRequiredBeginningSpace(node, first);
            }
            if (!options.spaced && isSpaced(first, second)) {
                reportNoBeginningSpace(node, first);
            }
        }

        if (isSameLine(penultimate, last)) {
            if (closingCurlyBraceMustBeSpaced && !isSpaced(penultimate, last)) {
                reportRequiredEndingSpace(node, last);
            }
            if (!closingCurlyBraceMustBeSpaced && isSpaced(penultimate, last)) {
                reportNoEndingSpace(node, last);
            }
        }
    }

    /**
     * Reports a given object node if spacing in curly braces is invalid.
     * @param {ASTNode} node - An ObjectExpression or ObjectPattern node to check.
     * @returns {void}
     */
    function checkForObject(node) {
        if (node.properties.length === 0) {
            return;
        }

        var firstSpecifier = node.properties[0],
            lastSpecifier = node.properties[node.properties.length - 1];

        var first = sourceCode.getTokenBefore(firstSpecifier),
            last = sourceCode.getTokenAfter(lastSpecifier);

        // support trailing commas
        if (last.value === ",") {
            last = sourceCode.getTokenAfter(last);
        }

        var second = sourceCode.getTokenAfter(first),
            penultimate = sourceCode.getTokenBefore(last);

        validateBraceSpacing(node, first, second, penultimate, last);
    }

    /**
     * Reports a given import node if spacing in curly braces is invalid.
     * @param {ASTNode} node - An ImportDeclaration node to check.
     * @returns {void}
     */
    function checkForImport(node) {
        if (node.specifiers.length === 0) {
            return;
        }

        var firstSpecifier = node.specifiers[0],
            lastSpecifier = node.specifiers[node.specifiers.length - 1];

        if (lastSpecifier.type !== "ImportSpecifier") {
            return;
        }
        if (firstSpecifier.type !== "ImportSpecifier") {
            firstSpecifier = node.specifiers[1];
        }

        var first = sourceCode.getTokenBefore(firstSpecifier),
            last = sourceCode.getTokenAfter(lastSpecifier);

        // to support a trailing comma.
        if (last.value === ",") {
            last = sourceCode.getTokenAfter(last);
        }

        var second = sourceCode.getTokenAfter(first),
            penultimate = sourceCode.getTokenBefore(last);

        validateBraceSpacing(node, first, second, penultimate, last);
    }

    /**
     * Reports a given export node if spacing in curly braces is invalid.
     * @param {ASTNode} node - An ExportNamedDeclaration node to check.
     * @returns {void}
     */
    function checkForExport(node) {
        if (node.specifiers.length === 0) {
            return;
        }

        var firstSpecifier = node.specifiers[0],
            lastSpecifier = node.specifiers[node.specifiers.length - 1],
            first = sourceCode.getTokenBefore(firstSpecifier),
            last = sourceCode.getTokenAfter(lastSpecifier);

        // export * as x from '...';
        // export x from '...';
        if (first.value === "export") {
            return;
        }

        // to support a trailing comma.
        if (last.value === ",") {
            last = sourceCode.getTokenAfter(last);
        }

        var second = sourceCode.getTokenAfter(first),
            penultimate = sourceCode.getTokenBefore(last);

        validateBraceSpacing(node, first, second, penultimate, last);
    }

    //--------------------------------------------------------------------------
    // Public
    //--------------------------------------------------------------------------

    return {
        // var {x} = y;
        ObjectPattern: checkForObject,

        // var y = {x: 'y'}
        ObjectExpression: checkForObject,

        // import {y} from 'x';
        ImportDeclaration: checkForImport,

        // export {name} from 'yo';
        ExportNamedDeclaration: checkForExport
    };

};

module.exports.schema = [
    {
        "enum": ["always", "never"]
    },
    {
        "type": "object",
        "properties": {
            "arraysInObjects": {
                "type": "boolean"
            },
            "objectsInObjects": {
                "type": "boolean"
            }
        },
        "additionalProperties": false
    }
];