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133 lines
4.4 KiB
133 lines
4.4 KiB
/**
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* @fileoverview Disallow construction of dense arrays using the Array constructor
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* @author Matt DuVall <http://www.mattduvall.com/>
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Requirements
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//------------------------------------------------------------------------------
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const {
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getVariableByName,
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isClosingParenToken,
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isOpeningParenToken,
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isStartOfExpressionStatement,
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needsPrecedingSemicolon
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} = require("./utils/ast-utils");
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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meta: {
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type: "suggestion",
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docs: {
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description: "Disallow `Array` constructors",
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recommended: false,
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url: "https://eslint.org/docs/latest/rules/no-array-constructor"
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},
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hasSuggestions: true,
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schema: [],
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messages: {
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preferLiteral: "The array literal notation [] is preferable.",
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useLiteral: "Replace with an array literal.",
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useLiteralAfterSemicolon: "Replace with an array literal, add preceding semicolon."
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}
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},
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create(context) {
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const sourceCode = context.sourceCode;
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/**
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* Gets the text between the calling parentheses of a CallExpression or NewExpression.
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* @param {ASTNode} node A CallExpression or NewExpression node.
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* @returns {string} The text between the calling parentheses, or an empty string if there are none.
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*/
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function getArgumentsText(node) {
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const lastToken = sourceCode.getLastToken(node);
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if (!isClosingParenToken(lastToken)) {
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return "";
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}
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let firstToken = node.callee;
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do {
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firstToken = sourceCode.getTokenAfter(firstToken);
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if (!firstToken || firstToken === lastToken) {
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return "";
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}
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} while (!isOpeningParenToken(firstToken));
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return sourceCode.text.slice(firstToken.range[1], lastToken.range[0]);
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}
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/**
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* Disallow construction of dense arrays using the Array constructor
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* @param {ASTNode} node node to evaluate
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* @returns {void}
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* @private
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*/
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function check(node) {
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if (
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node.callee.type !== "Identifier" ||
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node.callee.name !== "Array" ||
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node.arguments.length === 1 &&
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node.arguments[0].type !== "SpreadElement") {
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return;
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}
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const variable = getVariableByName(sourceCode.getScope(node), "Array");
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/*
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* Check if `Array` is a predefined global variable: predefined globals have no declarations,
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* meaning that the `identifiers` list of the variable object is empty.
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*/
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if (variable && variable.identifiers.length === 0) {
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const argsText = getArgumentsText(node);
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let fixText;
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let messageId;
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/*
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* Check if the suggested change should include a preceding semicolon or not.
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* Due to JavaScript's ASI rules, a missing semicolon may be inserted automatically
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* before an expression like `Array()` or `new Array()`, but not when the expression
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* is changed into an array literal like `[]`.
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*/
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if (isStartOfExpressionStatement(node) && needsPrecedingSemicolon(sourceCode, node)) {
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fixText = `;[${argsText}]`;
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messageId = "useLiteralAfterSemicolon";
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} else {
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fixText = `[${argsText}]`;
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messageId = "useLiteral";
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}
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context.report({
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node,
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messageId: "preferLiteral",
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suggest: [
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{
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messageId,
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fix: fixer => fixer.replaceText(node, fixText)
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}
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]
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});
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}
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}
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return {
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CallExpression: check,
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NewExpression: check
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};
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}
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};
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