78 lines
2.0 KiB
JavaScript
78 lines
2.0 KiB
JavaScript
/**
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* @fileoverview Rule to flag the use of empty character classes in regular expressions
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* @author Ian Christian Myers
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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 { RegExpParser, visitRegExpAST } = require('@eslint-community/regexpp');
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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const parser = new RegExpParser();
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const QUICK_TEST_REGEX = /\[\]/u;
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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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type: 'problem',
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docs: {
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description: 'Disallow empty character classes in regular expressions',
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recommended: true,
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url: 'https://eslint.org/docs/latest/rules/no-empty-character-class',
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},
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schema: [],
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messages: {
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unexpected: 'Empty class.',
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},
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},
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create(context) {
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return {
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'Literal[regex]'(node) {
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const { pattern, flags } = node.regex;
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if (!QUICK_TEST_REGEX.test(pattern)) {
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return;
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}
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let regExpAST;
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try {
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regExpAST = parser.parsePattern(pattern, 0, pattern.length, {
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unicode: flags.includes('u'),
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unicodeSets: flags.includes('v'),
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});
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} catch {
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// Ignore regular expressions that regexpp cannot parse
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return;
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}
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visitRegExpAST(regExpAST, {
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onCharacterClassEnter(characterClass) {
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if (
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!characterClass.negate &&
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characterClass.elements.length === 0
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) {
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context.report({ node, messageId: 'unexpected' });
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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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};
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