frontend/node_modules/eslint/lib/rules/comma-spacing.js

/**
 * @fileoverview Comma spacing - validates spacing before and after comma
 * @author Vignesh Anand aka vegetableman.
 * @deprecated in ESLint v8.53.0
 */
"use strict";

const astUtils = require("./utils/ast-utils");

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

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
	meta: {
		deprecated: {
			message: "Formatting rules are being moved out of ESLint core.",
			url: "https://eslint.org/blog/2023/10/deprecating-formatting-rules/",
			deprecatedSince: "8.53.0",
			availableUntil: "11.0.0",
			replacedBy: [
				{
					message:
						"ESLint Stylistic now maintains deprecated stylistic core rules.",
					url: "https://eslint.style/guide/migration",
					plugin: {
						name: "@stylistic/eslint-plugin",
						url: "https://eslint.style",
					},
					rule: {
						name: "comma-spacing",
						url: "https://eslint.style/rules/comma-spacing",
					},
				},
			],
		},
		type: "layout",

		docs: {
			description: "Enforce consistent spacing before and after commas",
			recommended: false,
			url: "https://eslint.org/docs/latest/rules/comma-spacing",
		},

		fixable: "whitespace",

		schema: [
			{
				type: "object",
				properties: {
					before: {
						type: "boolean",
						default: false,
					},
					after: {
						type: "boolean",
						default: true,
					},
				},
				additionalProperties: false,
			},
		],

		messages: {
			missing: "A space is required {{loc}} ','.",
			unexpected: "There should be no space {{loc}} ','.",
		},
	},

	create(context) {
		const sourceCode = context.sourceCode;
		const tokensAndComments = sourceCode.tokensAndComments;

		const options = {
			before: context.options[0] ? context.options[0].before : false,
			after: context.options[0] ? context.options[0].after : true,
		};

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

		// list of comma tokens to ignore for the check of leading whitespace
		const commaTokensToIgnore = [];

		/**
		 * Reports a spacing error with an appropriate message.
		 * @param {ASTNode} node The binary expression node to report.
		 * @param {string} loc Is the error "before" or "after" the comma?
		 * @param {ASTNode} otherNode The node at the left or right of `node`
		 * @returns {void}
		 * @private
		 */
		function report(node, loc, otherNode) {
			context.report({
				node,
				fix(fixer) {
					if (options[loc]) {
						if (loc === "before") {
							return fixer.insertTextBefore(node, " ");
						}
						return fixer.insertTextAfter(node, " ");
					}
					let start, end;
					const newText = "";

					if (loc === "before") {
						start = otherNode.range[1];
						end = node.range[0];
					} else {
						start = node.range[1];
						end = otherNode.range[0];
					}

					return fixer.replaceTextRange([start, end], newText);
				},
				messageId: options[loc] ? "missing" : "unexpected",
				data: {
					loc,
				},
			});
		}

		/**
		 * Adds null elements of the given ArrayExpression or ArrayPattern node to the ignore list.
		 * @param {ASTNode} node An ArrayExpression or ArrayPattern node.
		 * @returns {void}
		 */
		function addNullElementsToIgnoreList(node) {
			let previousToken = sourceCode.getFirstToken(node);

			node.elements.forEach(element => {
				let token;

				if (element === null) {
					token = sourceCode.getTokenAfter(previousToken);

					if (astUtils.isCommaToken(token)) {
						commaTokensToIgnore.push(token);
					}
				} else {
					token = sourceCode.getTokenAfter(element);
				}

				previousToken = token;
			});
		}

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

		return {
			"Program:exit"() {
				tokensAndComments.forEach((token, i) => {
					if (!astUtils.isCommaToken(token)) {
						return;
					}

					const previousToken = tokensAndComments[i - 1];
					const nextToken = tokensAndComments[i + 1];

					if (
						previousToken &&
						!astUtils.isCommaToken(previousToken) && // ignore spacing between two commas
						/*
						 * `commaTokensToIgnore` are ending commas of `null` elements (array holes/elisions).
						 * In addition to spacing between two commas, this can also ignore:
						 *
						 *   - Spacing after `[` (controlled by array-bracket-spacing)
						 *       Example: [ , ]
						 *                 ^
						 *   - Spacing after a comment (for backwards compatibility, this was possibly unintentional)
						 *       Example: [a, /* * / ,]
						 *                          ^
						 */
						!commaTokensToIgnore.includes(token) &&
						astUtils.isTokenOnSameLine(previousToken, token) &&
						options.before !==
							sourceCode.isSpaceBetween(previousToken, token)
					) {
						report(token, "before", previousToken);
					}

					if (
						nextToken &&
						!astUtils.isCommaToken(nextToken) && // ignore spacing between two commas
						!astUtils.isClosingParenToken(nextToken) && // controlled by space-in-parens
						!astUtils.isClosingBracketToken(nextToken) && // controlled by array-bracket-spacing
						!astUtils.isClosingBraceToken(nextToken) && // controlled by object-curly-spacing
						!(!options.after && nextToken.type === "Line") && // special case, allow space before line comment
						astUtils.isTokenOnSameLine(token, nextToken) &&
						options.after !==
							sourceCode.isSpaceBetween(token, nextToken)
					) {
						report(token, "after", nextToken);
					}
				});
			},
			ArrayExpression: addNullElementsToIgnoreList,
			ArrayPattern: addNullElementsToIgnoreList,
		};
	},
};