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							340 lines
						
					
					
						
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				/** | 
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 * @fileoverview Rule to forbid or enforce dangling commas. | 
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 * @author Ian Christian Myers | 
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 */ | 
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 | 
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"use strict"; | 
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 | 
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//------------------------------------------------------------------------------ | 
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// Requirements | 
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//------------------------------------------------------------------------------ | 
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 | 
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const lodash = require("lodash"); | 
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const astUtils = require("./utils/ast-utils"); | 
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 | 
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//------------------------------------------------------------------------------ | 
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// Helpers | 
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//------------------------------------------------------------------------------ | 
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 | 
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const DEFAULT_OPTIONS = Object.freeze({ | 
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    arrays: "never", | 
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    objects: "never", | 
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    imports: "never", | 
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    exports: "never", | 
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    functions: "never" | 
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}); | 
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 | 
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/** | 
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 * Checks whether or not a trailing comma is allowed in a given node. | 
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 * If the `lastItem` is `RestElement` or `RestProperty`, it disallows trailing commas. | 
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 * @param {ASTNode} lastItem The node of the last element in the given node. | 
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 * @returns {boolean} `true` if a trailing comma is allowed. | 
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 */ | 
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function isTrailingCommaAllowed(lastItem) { | 
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    return !( | 
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        lastItem.type === "RestElement" || | 
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        lastItem.type === "RestProperty" || | 
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        lastItem.type === "ExperimentalRestProperty" | 
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    ); | 
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} | 
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 | 
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/** | 
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 * Normalize option value. | 
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 * @param {string|Object|undefined} optionValue The 1st option value to normalize. | 
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 * @param {number} ecmaVersion The normalized ECMAScript version. | 
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 * @returns {Object} The normalized option value. | 
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 */ | 
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function normalizeOptions(optionValue, ecmaVersion) { | 
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    if (typeof optionValue === "string") { | 
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        return { | 
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            arrays: optionValue, | 
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            objects: optionValue, | 
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            imports: optionValue, | 
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            exports: optionValue, | 
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            functions: (!ecmaVersion || ecmaVersion < 8) ? "ignore" : optionValue | 
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        }; | 
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    } | 
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    if (typeof optionValue === "object" && optionValue !== null) { | 
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        return { | 
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            arrays: optionValue.arrays || DEFAULT_OPTIONS.arrays, | 
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            objects: optionValue.objects || DEFAULT_OPTIONS.objects, | 
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            imports: optionValue.imports || DEFAULT_OPTIONS.imports, | 
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            exports: optionValue.exports || DEFAULT_OPTIONS.exports, | 
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            functions: optionValue.functions || DEFAULT_OPTIONS.functions | 
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        }; | 
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    } | 
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 | 
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    return DEFAULT_OPTIONS; | 
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} | 
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 | 
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//------------------------------------------------------------------------------ | 
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// Rule Definition | 
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//------------------------------------------------------------------------------ | 
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 | 
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module.exports = { | 
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    meta: { | 
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        type: "layout", | 
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 | 
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        docs: { | 
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            description: "require or disallow trailing commas", | 
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            category: "Stylistic Issues", | 
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            recommended: false, | 
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            url: "https://eslint.org/docs/rules/comma-dangle" | 
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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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            definitions: { | 
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                value: { | 
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                    enum: [ | 
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                        "always-multiline", | 
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                        "always", | 
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                        "never", | 
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                        "only-multiline" | 
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                    ] | 
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                }, | 
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                valueWithIgnore: { | 
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                    enum: [ | 
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                        "always-multiline", | 
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                        "always", | 
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                        "ignore", | 
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                        "never", | 
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                        "only-multiline" | 
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                    ] | 
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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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                    oneOf: [ | 
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                        { | 
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                            $ref: "#/definitions/value" | 
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                        }, | 
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                        { | 
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                            type: "object", | 
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                            properties: { | 
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                                arrays: { $ref: "#/definitions/valueWithIgnore" }, | 
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                                objects: { $ref: "#/definitions/valueWithIgnore" }, | 
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                                imports: { $ref: "#/definitions/valueWithIgnore" }, | 
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                                exports: { $ref: "#/definitions/valueWithIgnore" }, | 
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                                functions: { $ref: "#/definitions/valueWithIgnore" } | 
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                            }, | 
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                            additionalProperties: false | 
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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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        messages: { | 
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            unexpected: "Unexpected trailing comma.", | 
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            missing: "Missing trailing comma." | 
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        } | 
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    }, | 
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 | 
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    create(context) { | 
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        const options = normalizeOptions(context.options[0], context.parserOptions.ecmaVersion); | 
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 | 
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        const sourceCode = context.getSourceCode(); | 
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 | 
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        /** | 
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         * Gets the last item of the given node. | 
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         * @param {ASTNode} node The node to get. | 
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         * @returns {ASTNode|null} The last node or null. | 
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         */ | 
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        function getLastItem(node) { | 
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            switch (node.type) { | 
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                case "ObjectExpression": | 
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                case "ObjectPattern": | 
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                    return lodash.last(node.properties); | 
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                case "ArrayExpression": | 
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                case "ArrayPattern": | 
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                    return lodash.last(node.elements); | 
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                case "ImportDeclaration": | 
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                case "ExportNamedDeclaration": | 
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                    return lodash.last(node.specifiers); | 
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                case "FunctionDeclaration": | 
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                case "FunctionExpression": | 
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                case "ArrowFunctionExpression": | 
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                    return lodash.last(node.params); | 
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                case "CallExpression": | 
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                case "NewExpression": | 
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                    return lodash.last(node.arguments); | 
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                default: | 
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                    return null; | 
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            } | 
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        } | 
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 | 
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        /** | 
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         * Gets the trailing comma token of the given node. | 
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         * If the trailing comma does not exist, this returns the token which is | 
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         * the insertion point of the trailing comma token. | 
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         * @param {ASTNode} node The node to get. | 
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         * @param {ASTNode} lastItem The last item of the node. | 
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         * @returns {Token} The trailing comma token or the insertion point. | 
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         */ | 
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        function getTrailingToken(node, lastItem) { | 
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            switch (node.type) { | 
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                case "ObjectExpression": | 
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                case "ArrayExpression": | 
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                case "CallExpression": | 
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                case "NewExpression": | 
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                    return sourceCode.getLastToken(node, 1); | 
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                default: { | 
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                    const nextToken = sourceCode.getTokenAfter(lastItem); | 
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 | 
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                    if (astUtils.isCommaToken(nextToken)) { | 
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                        return nextToken; | 
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                    } | 
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                    return sourceCode.getLastToken(lastItem); | 
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                } | 
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            } | 
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        } | 
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 | 
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        /** | 
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         * Checks whether or not a given node is multiline. | 
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         * This rule handles a given node as multiline when the closing parenthesis | 
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         * and the last element are not on the same line. | 
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         * @param {ASTNode} node A node to check. | 
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         * @returns {boolean} `true` if the node is multiline. | 
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         */ | 
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        function isMultiline(node) { | 
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            const lastItem = getLastItem(node); | 
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 | 
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            if (!lastItem) { | 
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                return false; | 
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            } | 
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 | 
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            const penultimateToken = getTrailingToken(node, lastItem); | 
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            const lastToken = sourceCode.getTokenAfter(penultimateToken); | 
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 | 
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            return lastToken.loc.end.line !== penultimateToken.loc.end.line; | 
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        } | 
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 | 
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        /** | 
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         * Reports a trailing comma if it exists. | 
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         * @param {ASTNode} node A node to check. Its type is one of | 
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         *   ObjectExpression, ObjectPattern, ArrayExpression, ArrayPattern, | 
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         *   ImportDeclaration, and ExportNamedDeclaration. | 
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         * @returns {void} | 
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         */ | 
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        function forbidTrailingComma(node) { | 
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            const lastItem = getLastItem(node); | 
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 | 
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            if (!lastItem || (node.type === "ImportDeclaration" && lastItem.type !== "ImportSpecifier")) { | 
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                return; | 
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            } | 
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 | 
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            const trailingToken = getTrailingToken(node, lastItem); | 
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 | 
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            if (astUtils.isCommaToken(trailingToken)) { | 
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                context.report({ | 
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                    node: lastItem, | 
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                    loc: trailingToken.loc, | 
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                    messageId: "unexpected", | 
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                    fix(fixer) { | 
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                        return fixer.remove(trailingToken); | 
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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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         * Reports the last element of a given node if it does not have a trailing | 
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         * comma. | 
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         * | 
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         * If a given node is `ArrayPattern` which has `RestElement`, the trailing | 
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         * comma is disallowed, so report if it exists. | 
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         * @param {ASTNode} node A node to check. Its type is one of | 
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         *   ObjectExpression, ObjectPattern, ArrayExpression, ArrayPattern, | 
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         *   ImportDeclaration, and ExportNamedDeclaration. | 
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         * @returns {void} | 
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         */ | 
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        function forceTrailingComma(node) { | 
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            const lastItem = getLastItem(node); | 
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 | 
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            if (!lastItem || (node.type === "ImportDeclaration" && lastItem.type !== "ImportSpecifier")) { | 
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                return; | 
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            } | 
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            if (!isTrailingCommaAllowed(lastItem)) { | 
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                forbidTrailingComma(node); | 
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                return; | 
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            } | 
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 | 
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            const trailingToken = getTrailingToken(node, lastItem); | 
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 | 
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            if (trailingToken.value !== ",") { | 
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                context.report({ | 
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                    node: lastItem, | 
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                    loc: { | 
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                        start: trailingToken.loc.end, | 
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                        end: astUtils.getNextLocation(sourceCode, trailingToken.loc.end) | 
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                    }, | 
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                    messageId: "missing", | 
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                    fix(fixer) { | 
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                        return fixer.insertTextAfter(trailingToken, ","); | 
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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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         * If a given node is multiline, reports the last element of a given node | 
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         * when it does not have a trailing comma. | 
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         * Otherwise, reports a trailing comma if it exists. | 
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         * @param {ASTNode} node A node to check. Its type is one of | 
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         *   ObjectExpression, ObjectPattern, ArrayExpression, ArrayPattern, | 
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         *   ImportDeclaration, and ExportNamedDeclaration. | 
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         * @returns {void} | 
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         */ | 
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        function forceTrailingCommaIfMultiline(node) { | 
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            if (isMultiline(node)) { | 
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                forceTrailingComma(node); | 
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            } else { | 
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                forbidTrailingComma(node); | 
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            } | 
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        } | 
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 | 
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        /** | 
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         * Only if a given node is not multiline, reports the last element of a given node | 
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         * when it does not have a trailing comma. | 
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         * Otherwise, reports a trailing comma if it exists. | 
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         * @param {ASTNode} node A node to check. Its type is one of | 
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         *   ObjectExpression, ObjectPattern, ArrayExpression, ArrayPattern, | 
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         *   ImportDeclaration, and ExportNamedDeclaration. | 
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         * @returns {void} | 
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         */ | 
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        function allowTrailingCommaIfMultiline(node) { | 
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            if (!isMultiline(node)) { | 
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                forbidTrailingComma(node); | 
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            } | 
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        } | 
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 | 
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        const predicate = { | 
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            always: forceTrailingComma, | 
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            "always-multiline": forceTrailingCommaIfMultiline, | 
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            "only-multiline": allowTrailingCommaIfMultiline, | 
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            never: forbidTrailingComma, | 
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            ignore: lodash.noop | 
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        }; | 
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 | 
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        return { | 
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            ObjectExpression: predicate[options.objects], | 
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            ObjectPattern: predicate[options.objects], | 
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 | 
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            ArrayExpression: predicate[options.arrays], | 
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            ArrayPattern: predicate[options.arrays], | 
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 | 
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            ImportDeclaration: predicate[options.imports], | 
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 | 
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            ExportNamedDeclaration: predicate[options.exports], | 
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 | 
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            FunctionDeclaration: predicate[options.functions], | 
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            FunctionExpression: predicate[options.functions], | 
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            ArrowFunctionExpression: predicate[options.functions], | 
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            CallExpression: predicate[options.functions], | 
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            NewExpression: predicate[options.functions] | 
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        }; | 
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    } | 
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};
 | 
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 |