84 lines
1.9 KiB
Plaintext
84 lines
1.9 KiB
Plaintext
/**
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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:
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"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(
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pattern,
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0,
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pattern.length,
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{
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unicode: flags.includes("u"),
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unicodeSets: flags.includes("v"),
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},
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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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