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Rslint

    require-unicode-regexp

    Unreleased

    Configuration

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

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'require-unicode-regexp': 'error',
    },
  },
]);

    Rule Details

    Enforces the use of the u or v flag on regular expressions.

    Examples of incorrect code for this rule:

    const a = /aaa/;
const b = /bbb/gi;
const c = new RegExp("ccc");
const d = new RegExp("ddd", "gi");

    Examples of correct code for this rule:

    const a = /aaa/u;
const b = /bbb/giu;
const c = new RegExp("ccc", "u");
const d = new RegExp("ddd", "giu");

const e = /aaa/v;
const f = /bbb/giv;
const g = new RegExp("ccc", "v");
const h = new RegExp("ddd", "giv");

// This rule ignores RegExp calls if the flags could not be evaluated to a static value.
function i(flags) {
  return new RegExp("eee", flags);
}

    Options

    This rule has one object option:

    • requireFlag: "u" or "v" — requires that particular flag instead of accepting either.

    Examples of incorrect code for this rule with { "requireFlag": "u" }:

    { "require-unicode-regexp": ["error", { "requireFlag": "u" }] }
    const foo = /foo/;
const fooRegexp = new RegExp("foo");
const bar = /bar/v;
const barRegexp = new RegExp("bar", "v");

    Examples of correct code for this rule with { "requireFlag": "u" }:

    { "require-unicode-regexp": ["error", { "requireFlag": "u" }] }
    const foo = /foo/u;
const fooRegexp = new RegExp("foo", "u");

    Examples of incorrect code for this rule with { "requireFlag": "v" }:

    { "require-unicode-regexp": ["error", { "requireFlag": "v" }] }
    const foo = /foo/;
const fooRegexp = new RegExp("foo");
const bar = /bar/u;
const barRegexp = new RegExp("bar", "u");

    Examples of correct code for this rule with { "requireFlag": "v" }:

    { "require-unicode-regexp": ["error", { "requireFlag": "v" }] }
    const foo = /foo/v;
const fooRegexp = new RegExp("foo", "v");

    Differences from ESLint

    • A pattern is judged against u-flag syntax when deciding whether the suggestion is safe, so one written in v-flag set notation — the difference operator ([\d--[3]]), a \q{...} string literal — is reported without a suggestion that ESLint would offer.
    • Unicode property escapes are recognized by their short aliases, so /\p{L}/ is offered the flag while /\p{Letter}/ and /\p{Script=Greek}/ are reported without a suggestion.
    • A suggested flag insertion into a template literal that interpolates an expression is refused whenever that template's cooked value already contains the opposite flag character, even when the interpolated expression's source text has no escape sequence of its own — ESLint only inspects the template's literal quasis for that escape check, this rule inspects the whole template source.

    Original Documentation