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							498 lines
						
					
					
						
							21 KiB
						
					
					
				/** | 
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 * @fileoverview Rule to enforce concise object methods and properties. | 
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 * @author Jamund Ferguson | 
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 */ | 
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 | 
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"use strict"; | 
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 | 
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const OPTIONS = { | 
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    always: "always", | 
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    never: "never", | 
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    methods: "methods", | 
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    properties: "properties", | 
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    consistent: "consistent", | 
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    consistentAsNeeded: "consistent-as-needed" | 
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}; | 
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 | 
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//------------------------------------------------------------------------------ | 
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// Requirements | 
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//------------------------------------------------------------------------------ | 
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const astUtils = require("./utils/ast-utils"); | 
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 | 
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//------------------------------------------------------------------------------ | 
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// Rule Definition | 
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//------------------------------------------------------------------------------ | 
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module.exports = { | 
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    meta: { | 
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        type: "suggestion", | 
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 | 
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        docs: { | 
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            description: "require or disallow method and property shorthand syntax for object literals", | 
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            category: "ECMAScript 6", | 
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            recommended: false, | 
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            url: "https://eslint.org/docs/rules/object-shorthand" | 
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        }, | 
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 | 
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        fixable: "code", | 
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 | 
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        schema: { | 
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            anyOf: [ | 
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                { | 
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                    type: "array", | 
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                    items: [ | 
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                        { | 
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                            enum: ["always", "methods", "properties", "never", "consistent", "consistent-as-needed"] | 
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                        } | 
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                    ], | 
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                    minItems: 0, | 
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                    maxItems: 1 | 
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                }, | 
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                { | 
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                    type: "array", | 
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                    items: [ | 
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                        { | 
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                            enum: ["always", "methods", "properties"] | 
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                        }, | 
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                        { | 
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                            type: "object", | 
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                            properties: { | 
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                                avoidQuotes: { | 
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                                    type: "boolean" | 
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                                } | 
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                            }, | 
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                            additionalProperties: false | 
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                        } | 
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                    ], | 
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                    minItems: 0, | 
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                    maxItems: 2 | 
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                }, | 
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                { | 
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                    type: "array", | 
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                    items: [ | 
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                        { | 
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                            enum: ["always", "methods"] | 
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                        }, | 
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                        { | 
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                            type: "object", | 
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                            properties: { | 
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                                ignoreConstructors: { | 
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                                    type: "boolean" | 
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                                }, | 
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                                avoidQuotes: { | 
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                                    type: "boolean" | 
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                                }, | 
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                                avoidExplicitReturnArrows: { | 
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                                    type: "boolean" | 
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                                } | 
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                            }, | 
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                            additionalProperties: false | 
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                        } | 
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                    ], | 
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                    minItems: 0, | 
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                    maxItems: 2 | 
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                } | 
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            ] | 
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        } | 
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    }, | 
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 | 
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    create(context) { | 
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        const APPLY = context.options[0] || OPTIONS.always; | 
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        const APPLY_TO_METHODS = APPLY === OPTIONS.methods || APPLY === OPTIONS.always; | 
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        const APPLY_TO_PROPS = APPLY === OPTIONS.properties || APPLY === OPTIONS.always; | 
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        const APPLY_NEVER = APPLY === OPTIONS.never; | 
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        const APPLY_CONSISTENT = APPLY === OPTIONS.consistent; | 
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        const APPLY_CONSISTENT_AS_NEEDED = APPLY === OPTIONS.consistentAsNeeded; | 
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 | 
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        const PARAMS = context.options[1] || {}; | 
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        const IGNORE_CONSTRUCTORS = PARAMS.ignoreConstructors; | 
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        const AVOID_QUOTES = PARAMS.avoidQuotes; | 
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        const AVOID_EXPLICIT_RETURN_ARROWS = !!PARAMS.avoidExplicitReturnArrows; | 
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        const sourceCode = context.getSourceCode(); | 
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 | 
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        //-------------------------------------------------------------------------- | 
						|
        // Helpers | 
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        //-------------------------------------------------------------------------- | 
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 | 
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        const CTOR_PREFIX_REGEX = /[^_$0-9]/u; | 
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 | 
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        /** | 
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         * Determines if the first character of the name is a capital letter. | 
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         * @param {string} name The name of the node to evaluate. | 
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         * @returns {boolean} True if the first character of the property name is a capital letter, false if not. | 
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         * @private | 
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         */ | 
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        function isConstructor(name) { | 
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            const match = CTOR_PREFIX_REGEX.exec(name); | 
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 | 
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            // Not a constructor if name has no characters apart from '_', '$' and digits e.g. '_', '$$', '_8' | 
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            if (!match) { | 
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                return false; | 
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            } | 
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 | 
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            const firstChar = name.charAt(match.index); | 
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 | 
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            return firstChar === firstChar.toUpperCase(); | 
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        } | 
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 | 
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        /** | 
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         * Determines if the property can have a shorthand form. | 
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         * @param {ASTNode} property Property AST node | 
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         * @returns {boolean} True if the property can have a shorthand form | 
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         * @private | 
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         * | 
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         */ | 
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        function canHaveShorthand(property) { | 
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            return (property.kind !== "set" && property.kind !== "get" && property.type !== "SpreadElement" && property.type !== "SpreadProperty" && property.type !== "ExperimentalSpreadProperty"); | 
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        } | 
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 | 
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        /** | 
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         * Checks whether a node is a string literal. | 
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         * @param   {ASTNode} node Any AST node. | 
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         * @returns {boolean} `true` if it is a string literal. | 
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         */ | 
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        function isStringLiteral(node) { | 
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            return node.type === "Literal" && typeof node.value === "string"; | 
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        } | 
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 | 
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        /** | 
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         * Determines if the property is a shorthand or not. | 
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         * @param {ASTNode} property Property AST node | 
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         * @returns {boolean} True if the property is considered shorthand, false if not. | 
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         * @private | 
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         * | 
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         */ | 
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        function isShorthand(property) { | 
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 | 
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            // property.method is true when `{a(){}}`. | 
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            return (property.shorthand || property.method); | 
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        } | 
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 | 
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        /** | 
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         * Determines if the property's key and method or value are named equally. | 
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         * @param {ASTNode} property Property AST node | 
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         * @returns {boolean} True if the key and value are named equally, false if not. | 
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         * @private | 
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         * | 
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         */ | 
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        function isRedundant(property) { | 
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            const value = property.value; | 
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 | 
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            if (value.type === "FunctionExpression") { | 
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                return !value.id; // Only anonymous should be shorthand method. | 
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            } | 
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            if (value.type === "Identifier") { | 
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                return astUtils.getStaticPropertyName(property) === value.name; | 
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            } | 
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 | 
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            return false; | 
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        } | 
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 | 
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        /** | 
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         * Ensures that an object's properties are consistently shorthand, or not shorthand at all. | 
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         * @param   {ASTNode} node Property AST node | 
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         * @param   {boolean} checkRedundancy Whether to check longform redundancy | 
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         * @returns {void} | 
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         * | 
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         */ | 
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        function checkConsistency(node, checkRedundancy) { | 
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 | 
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            // We are excluding getters/setters and spread properties as they are considered neither longform nor shorthand. | 
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            const properties = node.properties.filter(canHaveShorthand); | 
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 | 
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            // Do we still have properties left after filtering the getters and setters? | 
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            if (properties.length > 0) { | 
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                const shorthandProperties = properties.filter(isShorthand); | 
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 | 
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                /* | 
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                 * If we do not have an equal number of longform properties as | 
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                 * shorthand properties, we are using the annotations inconsistently | 
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                 */ | 
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                if (shorthandProperties.length !== properties.length) { | 
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 | 
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                    // We have at least 1 shorthand property | 
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                    if (shorthandProperties.length > 0) { | 
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                        context.report({ node, message: "Unexpected mix of shorthand and non-shorthand properties." }); | 
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                    } else if (checkRedundancy) { | 
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 | 
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                        /* | 
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                         * If all properties of the object contain a method or value with a name matching it's key, | 
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                         * all the keys are redundant. | 
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                         */ | 
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                        const canAlwaysUseShorthand = properties.every(isRedundant); | 
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 | 
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                        if (canAlwaysUseShorthand) { | 
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                            context.report({ node, message: "Expected shorthand for all properties." }); | 
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                        } | 
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                    } | 
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                } | 
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            } | 
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        } | 
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 | 
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        /** | 
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         * Fixes a FunctionExpression node by making it into a shorthand property. | 
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         * @param {SourceCodeFixer} fixer The fixer object | 
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         * @param {ASTNode} node A `Property` node that has a `FunctionExpression` or `ArrowFunctionExpression` as its value | 
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         * @returns {Object} A fix for this node | 
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         */ | 
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        function makeFunctionShorthand(fixer, node) { | 
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            const firstKeyToken = node.computed | 
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                ? sourceCode.getFirstToken(node, astUtils.isOpeningBracketToken) | 
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                : sourceCode.getFirstToken(node.key); | 
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            const lastKeyToken = node.computed | 
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                ? sourceCode.getFirstTokenBetween(node.key, node.value, astUtils.isClosingBracketToken) | 
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                : sourceCode.getLastToken(node.key); | 
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            const keyText = sourceCode.text.slice(firstKeyToken.range[0], lastKeyToken.range[1]); | 
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            let keyPrefix = ""; | 
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 | 
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            // key: /* */ () => {} | 
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            if (sourceCode.commentsExistBetween(lastKeyToken, node.value)) { | 
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                return null; | 
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            } | 
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 | 
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            if (node.value.async) { | 
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                keyPrefix += "async "; | 
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            } | 
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            if (node.value.generator) { | 
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                keyPrefix += "*"; | 
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            } | 
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 | 
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            const fixRange = [firstKeyToken.range[0], node.range[1]]; | 
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            const methodPrefix = keyPrefix + keyText; | 
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 | 
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            if (node.value.type === "FunctionExpression") { | 
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                const functionToken = sourceCode.getTokens(node.value).find(token => token.type === "Keyword" && token.value === "function"); | 
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                const tokenBeforeParams = node.value.generator ? sourceCode.getTokenAfter(functionToken) : functionToken; | 
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 | 
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                return fixer.replaceTextRange( | 
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                    fixRange, | 
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                    methodPrefix + sourceCode.text.slice(tokenBeforeParams.range[1], node.value.range[1]) | 
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                ); | 
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            } | 
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 | 
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            const arrowToken = sourceCode.getTokenBefore(node.value.body, astUtils.isArrowToken); | 
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            const fnBody = sourceCode.text.slice(arrowToken.range[1], node.value.range[1]); | 
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 | 
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            let shouldAddParensAroundParameters = false; | 
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            let tokenBeforeParams; | 
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 | 
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            if (node.value.params.length === 0) { | 
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                tokenBeforeParams = sourceCode.getFirstToken(node.value, astUtils.isOpeningParenToken); | 
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            } else { | 
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                tokenBeforeParams = sourceCode.getTokenBefore(node.value.params[0]); | 
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            } | 
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 | 
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            if (node.value.params.length === 1) { | 
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                const hasParen = astUtils.isOpeningParenToken(tokenBeforeParams); | 
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                const isTokenOutsideNode = tokenBeforeParams.range[0] < node.range[0]; | 
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 | 
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                shouldAddParensAroundParameters = !hasParen || isTokenOutsideNode; | 
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            } | 
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 | 
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            const sliceStart = shouldAddParensAroundParameters | 
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                ? node.value.params[0].range[0] | 
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                : tokenBeforeParams.range[0]; | 
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            const sliceEnd = sourceCode.getTokenBefore(arrowToken).range[1]; | 
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 | 
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            const oldParamText = sourceCode.text.slice(sliceStart, sliceEnd); | 
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            const newParamText = shouldAddParensAroundParameters ? `(${oldParamText})` : oldParamText; | 
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 | 
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            return fixer.replaceTextRange( | 
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                fixRange, | 
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                methodPrefix + newParamText + fnBody | 
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            ); | 
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 | 
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        } | 
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 | 
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        /** | 
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         * Fixes a FunctionExpression node by making it into a longform property. | 
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         * @param {SourceCodeFixer} fixer The fixer object | 
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         * @param {ASTNode} node A `Property` node that has a `FunctionExpression` as its value | 
						|
         * @returns {Object} A fix for this node | 
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         */ | 
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        function makeFunctionLongform(fixer, node) { | 
						|
            const firstKeyToken = node.computed ? sourceCode.getTokens(node).find(token => token.value === "[") : sourceCode.getFirstToken(node.key); | 
						|
            const lastKeyToken = node.computed ? sourceCode.getTokensBetween(node.key, node.value).find(token => token.value === "]") : sourceCode.getLastToken(node.key); | 
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            const keyText = sourceCode.text.slice(firstKeyToken.range[0], lastKeyToken.range[1]); | 
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            let functionHeader = "function"; | 
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 | 
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            if (node.value.async) { | 
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                functionHeader = `async ${functionHeader}`; | 
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            } | 
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            if (node.value.generator) { | 
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                functionHeader = `${functionHeader}*`; | 
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            } | 
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 | 
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            return fixer.replaceTextRange([node.range[0], lastKeyToken.range[1]], `${keyText}: ${functionHeader}`); | 
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        } | 
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 | 
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        /* | 
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         * To determine whether a given arrow function has a lexical identifier (`this`, `arguments`, `super`, or `new.target`), | 
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         * create a stack of functions that define these identifiers (i.e. all functions except arrow functions) as the AST is | 
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         * traversed. Whenever a new function is encountered, create a new entry on the stack (corresponding to a different lexical | 
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         * scope of `this`), and whenever a function is exited, pop that entry off the stack. When an arrow function is entered, | 
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         * keep a reference to it on the current stack entry, and remove that reference when the arrow function is exited. | 
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         * When a lexical identifier is encountered, mark all the arrow functions on the current stack entry by adding them | 
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         * to an `arrowsWithLexicalIdentifiers` set. Any arrow function in that set will not be reported by this rule, | 
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         * because converting it into a method would change the value of one of the lexical identifiers. | 
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         */ | 
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        const lexicalScopeStack = []; | 
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        const arrowsWithLexicalIdentifiers = new WeakSet(); | 
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        const argumentsIdentifiers = new WeakSet(); | 
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 | 
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        /** | 
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         * Enters a function. This creates a new lexical identifier scope, so a new Set of arrow functions is pushed onto the stack. | 
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         * Also, this marks all `arguments` identifiers so that they can be detected later. | 
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         * @returns {void} | 
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         */ | 
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        function enterFunction() { | 
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            lexicalScopeStack.unshift(new Set()); | 
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            context.getScope().variables.filter(variable => variable.name === "arguments").forEach(variable => { | 
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                variable.references.map(ref => ref.identifier).forEach(identifier => argumentsIdentifiers.add(identifier)); | 
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            }); | 
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        } | 
						|
 | 
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        /** | 
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         * Exits a function. This pops the current set of arrow functions off the lexical scope stack. | 
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         * @returns {void} | 
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         */ | 
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        function exitFunction() { | 
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            lexicalScopeStack.shift(); | 
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        } | 
						|
 | 
						|
        /** | 
						|
         * Marks the current function as having a lexical keyword. This implies that all arrow functions | 
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         * in the current lexical scope contain a reference to this lexical keyword. | 
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         * @returns {void} | 
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         */ | 
						|
        function reportLexicalIdentifier() { | 
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            lexicalScopeStack[0].forEach(arrowFunction => arrowsWithLexicalIdentifiers.add(arrowFunction)); | 
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        } | 
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 | 
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        //-------------------------------------------------------------------------- | 
						|
        // Public | 
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        //-------------------------------------------------------------------------- | 
						|
 | 
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        return { | 
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            Program: enterFunction, | 
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            FunctionDeclaration: enterFunction, | 
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            FunctionExpression: enterFunction, | 
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            "Program:exit": exitFunction, | 
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            "FunctionDeclaration:exit": exitFunction, | 
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            "FunctionExpression:exit": exitFunction, | 
						|
 | 
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            ArrowFunctionExpression(node) { | 
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                lexicalScopeStack[0].add(node); | 
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            }, | 
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            "ArrowFunctionExpression:exit"(node) { | 
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                lexicalScopeStack[0].delete(node); | 
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            }, | 
						|
 | 
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            ThisExpression: reportLexicalIdentifier, | 
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            Super: reportLexicalIdentifier, | 
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            MetaProperty(node) { | 
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                if (node.meta.name === "new" && node.property.name === "target") { | 
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                    reportLexicalIdentifier(); | 
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                } | 
						|
            }, | 
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            Identifier(node) { | 
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                if (argumentsIdentifiers.has(node)) { | 
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                    reportLexicalIdentifier(); | 
						|
                } | 
						|
            }, | 
						|
 | 
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            ObjectExpression(node) { | 
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                if (APPLY_CONSISTENT) { | 
						|
                    checkConsistency(node, false); | 
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                } else if (APPLY_CONSISTENT_AS_NEEDED) { | 
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                    checkConsistency(node, true); | 
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                } | 
						|
            }, | 
						|
 | 
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            "Property:exit"(node) { | 
						|
                const isConciseProperty = node.method || node.shorthand; | 
						|
 | 
						|
                // Ignore destructuring assignment | 
						|
                if (node.parent.type === "ObjectPattern") { | 
						|
                    return; | 
						|
                } | 
						|
 | 
						|
                // getters and setters are ignored | 
						|
                if (node.kind === "get" || node.kind === "set") { | 
						|
                    return; | 
						|
                } | 
						|
 | 
						|
                // only computed methods can fail the following checks | 
						|
                if (node.computed && node.value.type !== "FunctionExpression" && node.value.type !== "ArrowFunctionExpression") { | 
						|
                    return; | 
						|
                } | 
						|
 | 
						|
                //-------------------------------------------------------------- | 
						|
                // Checks for property/method shorthand. | 
						|
                if (isConciseProperty) { | 
						|
                    if (node.method && (APPLY_NEVER || AVOID_QUOTES && isStringLiteral(node.key))) { | 
						|
                        const message = APPLY_NEVER ? "Expected longform method syntax." : "Expected longform method syntax for string literal keys."; | 
						|
 | 
						|
                        // { x() {} } should be written as { x: function() {} } | 
						|
                        context.report({ | 
						|
                            node, | 
						|
                            message, | 
						|
                            fix: fixer => makeFunctionLongform(fixer, node) | 
						|
                        }); | 
						|
                    } else if (APPLY_NEVER) { | 
						|
 | 
						|
                        // { x } should be written as { x: x } | 
						|
                        context.report({ | 
						|
                            node, | 
						|
                            message: "Expected longform property syntax.", | 
						|
                            fix: fixer => fixer.insertTextAfter(node.key, `: ${node.key.name}`) | 
						|
                        }); | 
						|
                    } | 
						|
                } else if (APPLY_TO_METHODS && !node.value.id && (node.value.type === "FunctionExpression" || node.value.type === "ArrowFunctionExpression")) { | 
						|
                    if (IGNORE_CONSTRUCTORS && node.key.type === "Identifier" && isConstructor(node.key.name)) { | 
						|
                        return; | 
						|
                    } | 
						|
                    if (AVOID_QUOTES && isStringLiteral(node.key)) { | 
						|
                        return; | 
						|
                    } | 
						|
 | 
						|
                    // {[x]: function(){}} should be written as {[x]() {}} | 
						|
                    if (node.value.type === "FunctionExpression" || | 
						|
                        node.value.type === "ArrowFunctionExpression" && | 
						|
                        node.value.body.type === "BlockStatement" && | 
						|
                        AVOID_EXPLICIT_RETURN_ARROWS && | 
						|
                        !arrowsWithLexicalIdentifiers.has(node.value) | 
						|
                    ) { | 
						|
                        context.report({ | 
						|
                            node, | 
						|
                            message: "Expected method shorthand.", | 
						|
                            fix: fixer => makeFunctionShorthand(fixer, node) | 
						|
                        }); | 
						|
                    } | 
						|
                } else if (node.value.type === "Identifier" && node.key.name === node.value.name && APPLY_TO_PROPS) { | 
						|
 | 
						|
                    // {x: x} should be written as {x} | 
						|
                    context.report({ | 
						|
                        node, | 
						|
                        message: "Expected property shorthand.", | 
						|
                        fix(fixer) { | 
						|
                            return fixer.replaceText(node, node.value.name); | 
						|
                        } | 
						|
                    }); | 
						|
                } else if (node.value.type === "Identifier" && node.key.type === "Literal" && node.key.value === node.value.name && APPLY_TO_PROPS) { | 
						|
                    if (AVOID_QUOTES) { | 
						|
                        return; | 
						|
                    } | 
						|
 | 
						|
                    // {"x": x} should be written as {x} | 
						|
                    context.report({ | 
						|
                        node, | 
						|
                        message: "Expected property shorthand.", | 
						|
                        fix(fixer) { | 
						|
                            return fixer.replaceText(node, node.value.name); | 
						|
                        } | 
						|
                    }); | 
						|
                } | 
						|
            } | 
						|
        }; | 
						|
    } | 
						|
};
 | 
						|
 |