#prefer-regexp-test

#Configuration

import { defineConfig, unicornPlugin } from '@rslint/core';

export default defineConfig([
  unicornPlugin.configs.recommended,
  {
    rules: {
      'unicorn/prefer-regexp-test': 'error',
    },
  },
]);

#Rule details

Prefer RegExp#test() over String#match(), String#search(), and RegExp#exec() when only checking whether a pattern matches.

Examples of incorrect code for this rule:

if (string.match(/unicorn/)) {}
if (/unicorn/.exec(string)) {}
if (string.match(/unicorn/).length > 0) {}
if (string.search(/unicorn/) !== -1) {}

Examples of correct code for this rule:

if (/unicorn/.test(string)) {}

The rule recognizes boolean contexts and comparisons of search() results with -1 or 0. Calls with known incompatible receivers or arguments are ignored.

Static regular expressions without the g flag can be fixed automatically. For search(), the y flag also prevents automatic fixes. Unknown expressions and expressions with these flags receive suggestions. Positive .length checks receive suggestions because replacing them can change how a failed match is handled. Comments that would be removed prevent the fix or suggestion.

#Options

This rule has no options.

#Differences from upstream

Expressions inside Vue and Svelte templates are not checked. Expressions in JavaScript, JSX, and TypeScript files are checked.

String intersections that resolve to string, such as string & unknown, are treated as strings. The following call is left unchanged instead of receiving a suggestion to use .test():

function f(pattern: string & unknown) {
  if (text.match(pattern)) {}
}

Regular expressions with modified properties or uses of compile() receive suggestions instead of automatic fixes, including when a variable alias is used. Changing matching hooks or flags can make .test() return different results:

const re = /x/;
re.compile('x', 'g');
if ('x'.match(re)) {}

#Original documentation

• eslint-plugin-unicorn: prefer-regexp-test
• Source code