140 lines
4.0 KiB
JavaScript
140 lines
4.0 KiB
JavaScript
/**
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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('../types').Rule.RuleModule} */
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module.exports = {
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meta: {
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dialects: ['javascript', 'typescript'],
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language: 'javascript',
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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:
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'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.typeArguments ||
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(node.arguments.length === 1 &&
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node.arguments[0].type !== 'SpreadElement')
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) {
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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 (
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isStartOfExpressionStatement(node) &&
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needsPrecedingSemicolon(sourceCode, node)
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) {
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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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