311 lines
12 KiB
JavaScript
311 lines
12 KiB
JavaScript
/**
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* @fileoverview Comma style - enforces comma styles of two types: last and first
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* @author Vignesh Anand aka vegetableman
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*/
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"use strict";
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const astUtils = require("./utils/ast-utils");
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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: "layout",
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docs: {
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description: "enforce consistent comma style",
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category: "Stylistic Issues",
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recommended: false,
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url: "https://eslint.org/docs/rules/comma-style"
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},
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fixable: "code",
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schema: [
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{
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enum: ["first", "last"]
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},
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{
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type: "object",
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properties: {
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exceptions: {
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type: "object",
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additionalProperties: {
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type: "boolean"
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}
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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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messages: {
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unexpectedLineBeforeAndAfterComma: "Bad line breaking before and after ','.",
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expectedCommaFirst: "',' should be placed first.",
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expectedCommaLast: "',' should be placed last."
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}
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},
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create(context) {
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const style = context.options[0] || "last",
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sourceCode = context.getSourceCode();
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const exceptions = {
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ArrayPattern: true,
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ArrowFunctionExpression: true,
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CallExpression: true,
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FunctionDeclaration: true,
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FunctionExpression: true,
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ImportDeclaration: true,
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ObjectPattern: true,
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NewExpression: true
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};
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if (context.options.length === 2 && Object.prototype.hasOwnProperty.call(context.options[1], "exceptions")) {
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const keys = Object.keys(context.options[1].exceptions);
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for (let i = 0; i < keys.length; i++) {
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exceptions[keys[i]] = context.options[1].exceptions[keys[i]];
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}
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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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* Modified text based on the style
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* @param {string} styleType Style type
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* @param {string} text Source code text
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* @returns {string} modified text
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* @private
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*/
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function getReplacedText(styleType, text) {
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switch (styleType) {
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case "between":
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return `,${text.replace(astUtils.LINEBREAK_MATCHER, "")}`;
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case "first":
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return `${text},`;
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case "last":
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return `,${text}`;
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default:
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return "";
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}
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}
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/**
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* Determines the fixer function for a given style.
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* @param {string} styleType comma style
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* @param {ASTNode} previousItemToken The token to check.
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* @param {ASTNode} commaToken The token to check.
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* @param {ASTNode} currentItemToken The token to check.
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* @returns {Function} Fixer function
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* @private
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*/
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function getFixerFunction(styleType, previousItemToken, commaToken, currentItemToken) {
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const text =
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sourceCode.text.slice(previousItemToken.range[1], commaToken.range[0]) +
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sourceCode.text.slice(commaToken.range[1], currentItemToken.range[0]);
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const range = [previousItemToken.range[1], currentItemToken.range[0]];
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return function(fixer) {
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return fixer.replaceTextRange(range, getReplacedText(styleType, text));
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};
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}
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/**
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* Validates the spacing around single items in lists.
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* @param {Token} previousItemToken The last token from the previous item.
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* @param {Token} commaToken The token representing the comma.
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* @param {Token} currentItemToken The first token of the current item.
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* @param {Token} reportItem The item to use when reporting an error.
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* @returns {void}
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* @private
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*/
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function validateCommaItemSpacing(previousItemToken, commaToken, currentItemToken, reportItem) {
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// if single line
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if (astUtils.isTokenOnSameLine(commaToken, currentItemToken) &&
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astUtils.isTokenOnSameLine(previousItemToken, commaToken)) {
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// do nothing.
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} else if (!astUtils.isTokenOnSameLine(commaToken, currentItemToken) &&
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!astUtils.isTokenOnSameLine(previousItemToken, commaToken)) {
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const comment = sourceCode.getCommentsAfter(commaToken)[0];
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const styleType = comment && comment.type === "Block" && astUtils.isTokenOnSameLine(commaToken, comment)
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? style
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: "between";
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// lone comma
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context.report({
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node: reportItem,
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loc: commaToken.loc,
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messageId: "unexpectedLineBeforeAndAfterComma",
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fix: getFixerFunction(styleType, previousItemToken, commaToken, currentItemToken)
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});
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} else if (style === "first" && !astUtils.isTokenOnSameLine(commaToken, currentItemToken)) {
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context.report({
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node: reportItem,
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loc: commaToken.loc,
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messageId: "expectedCommaFirst",
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fix: getFixerFunction(style, previousItemToken, commaToken, currentItemToken)
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});
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} else if (style === "last" && astUtils.isTokenOnSameLine(commaToken, currentItemToken)) {
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context.report({
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node: reportItem,
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loc: commaToken.loc,
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messageId: "expectedCommaLast",
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fix: getFixerFunction(style, previousItemToken, commaToken, currentItemToken)
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});
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}
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}
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/**
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* Checks the comma placement with regards to a declaration/property/element
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* @param {ASTNode} node The binary expression node to check
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* @param {string} property The property of the node containing child nodes.
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* @private
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* @returns {void}
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*/
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function validateComma(node, property) {
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const items = node[property],
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arrayLiteral = (node.type === "ArrayExpression" || node.type === "ArrayPattern");
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if (items.length > 1 || arrayLiteral) {
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// seed as opening [
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let previousItemToken = sourceCode.getFirstToken(node);
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items.forEach(item => {
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const commaToken = item ? sourceCode.getTokenBefore(item) : previousItemToken,
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currentItemToken = item ? sourceCode.getFirstToken(item) : sourceCode.getTokenAfter(commaToken),
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reportItem = item || currentItemToken;
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/*
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* This works by comparing three token locations:
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* - previousItemToken is the last token of the previous item
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* - commaToken is the location of the comma before the current item
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* - currentItemToken is the first token of the current item
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*
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* These values get switched around if item is undefined.
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* previousItemToken will refer to the last token not belonging
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* to the current item, which could be a comma or an opening
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* square bracket. currentItemToken could be a comma.
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*
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* All comparisons are done based on these tokens directly, so
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* they are always valid regardless of an undefined item.
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*/
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if (astUtils.isCommaToken(commaToken)) {
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validateCommaItemSpacing(previousItemToken, commaToken, currentItemToken, reportItem);
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}
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if (item) {
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const tokenAfterItem = sourceCode.getTokenAfter(item, astUtils.isNotClosingParenToken);
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previousItemToken = tokenAfterItem
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? sourceCode.getTokenBefore(tokenAfterItem)
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: sourceCode.ast.tokens[sourceCode.ast.tokens.length - 1];
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} else {
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previousItemToken = currentItemToken;
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}
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});
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/*
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* Special case for array literals that have empty last items, such
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* as [ 1, 2, ]. These arrays only have two items show up in the
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* AST, so we need to look at the token to verify that there's no
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* dangling comma.
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*/
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if (arrayLiteral) {
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const lastToken = sourceCode.getLastToken(node),
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nextToLastToken = sourceCode.getTokenBefore(lastToken);
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if (astUtils.isCommaToken(nextToLastToken)) {
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validateCommaItemSpacing(
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sourceCode.getTokenBefore(nextToLastToken),
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nextToLastToken,
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lastToken,
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lastToken
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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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// Public
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//--------------------------------------------------------------------------
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const nodes = {};
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if (!exceptions.VariableDeclaration) {
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nodes.VariableDeclaration = function(node) {
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validateComma(node, "declarations");
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};
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}
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if (!exceptions.ObjectExpression) {
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nodes.ObjectExpression = function(node) {
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validateComma(node, "properties");
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};
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}
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if (!exceptions.ObjectPattern) {
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nodes.ObjectPattern = function(node) {
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validateComma(node, "properties");
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};
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}
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if (!exceptions.ArrayExpression) {
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nodes.ArrayExpression = function(node) {
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validateComma(node, "elements");
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};
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}
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if (!exceptions.ArrayPattern) {
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nodes.ArrayPattern = function(node) {
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validateComma(node, "elements");
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};
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}
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if (!exceptions.FunctionDeclaration) {
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nodes.FunctionDeclaration = function(node) {
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validateComma(node, "params");
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};
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}
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if (!exceptions.FunctionExpression) {
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nodes.FunctionExpression = function(node) {
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validateComma(node, "params");
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};
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}
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if (!exceptions.ArrowFunctionExpression) {
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nodes.ArrowFunctionExpression = function(node) {
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validateComma(node, "params");
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};
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}
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if (!exceptions.CallExpression) {
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nodes.CallExpression = function(node) {
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validateComma(node, "arguments");
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};
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}
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if (!exceptions.ImportDeclaration) {
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nodes.ImportDeclaration = function(node) {
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validateComma(node, "specifiers");
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};
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}
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if (!exceptions.NewExpression) {
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nodes.NewExpression = function(node) {
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validateComma(node, "arguments");
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};
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}
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return nodes;
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}
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};
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