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Rslint

    prefer-named-capture-group

    Added in v0.9.1

    Configuration

    rslint.config.ts
    import { defineConfig, js } from '@rslint/core';

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'prefer-named-capture-group': 'error',
    },
  },
]);

    Rule Details

    This rule enforces using named capture groups instead of numbered capture groups in regular expressions. Named capture groups make a regular expression's intent easier to read, and make the captured values easier to retrieve (match.groups.name instead of a numbered index that shifts if the pattern changes).

    This rule checks regex literals as well as string patterns passed to the RegExp constructor, including stable local aliases initialized from RegExp or globalThis/window/self/global, when the pattern is statically determinable.

    Examples of incorrect code for this rule:

    const foo = /(ba[rz])/;
const bar = new RegExp("(ba[rz])");
const baz = RegExp("(ba[rz])");

foo.exec("bar")[1]; // Retrieve the group result.

    Examples of correct code for this rule:

    const foo = /(?<id>ba[rz])/;
const bar = new RegExp("(?<id>ba[rz])");
const baz = RegExp("(?<id>ba[rz])");
const xyz = /xyz(?:zy|abc)/;

foo.exec("bar").groups.id; // Retrieve the group result.

    Options

    This rule has no configurable options.

    Differences from ESLint

    • ESLint reports some indirect constructor calls that rslint currently skips. This includes aliases created by destructuring, a parameter default, or a separate assignment, as well as an alias assigned again anywhere in the file.
    • If a single call can resolve to the global RegExp through more than 128 logical or conditional branches, rslint reports at most 128 warnings for each unnamed capture group.
    • A pattern that uses a Unicode property added after rslint's bundled Unicode version may be accepted by the target runtime but not reported by this rule.
    • Suggested edits can differ from ESLint: rslint omits an edit that would make the pattern invalid and may choose a different temporary group name to avoid reusing one already present in the pattern.

    When Not To Use It

    If you are targeting ECMAScript 2017 or older environments, you should disable this rule, because named capture groups are only supported in ECMAScript 2018 and newer environments.

    Original Documentation