Skip to content
Permalink
9bfb9ba527
Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
Go to file
 
 
Cannot retrieve contributors at this time
76 lines (59 sloc) 2.23 KB
/**
* @fileoverview Rule to flag the use of empty character classes in regular expressions
* @author Ian Christian Myers
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const { RegExpParser, visitRegExpAST } = require("@eslint-community/regexpp");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
const parser = new RegExpParser();
const QUICK_TEST_REGEX = /\[\]/u;
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "problem",
docs: {
description: "Disallow empty character classes in regular expressions",
recommended: true,
url: "https://eslint.org/docs/latest/rules/no-empty-character-class"
},
schema: [],
messages: {
unexpected: "Empty class."
}
},
create(context) {
return {
"Literal[regex]"(node) {
const { pattern, flags } = node.regex;
if (!QUICK_TEST_REGEX.test(pattern)) {
return;
}
let regExpAST;
try {
regExpAST = parser.parsePattern(pattern, 0, pattern.length, {
unicode: flags.includes("u"),
unicodeSets: flags.includes("v")
});
} catch {
// Ignore regular expressions that regexpp cannot parse
return;
}
visitRegExpAST(regExpAST, {
onCharacterClassEnter(characterClass) {
if (!characterClass.negate && characterClass.elements.length === 0) {
context.report({ node, messageId: "unexpected" });
}
}
});
}
};
}
};