eslint-plugin-unicorn

55.0.0 verified Sat Apr 25 auth: no javascript

ESLint plugin providing more than 100 powerful rules for enforcing consistent, error-free code style and catching common mistakes. Current stable version is 55.0.0, with frequent releases (often multiple per month). Key differentiators include a broad focus beyond stylistic concerns (e.g., security, performance, best practices), automatic fixing for many rules, and strong integration with XO. It requires ESLint >=8.56.0 and Node >=18.18, and ships TypeScript definitions.

Common errors

error Oops! Something went wrong! :( ESLint: 8.x.x. eslint-plugin-unicorn: 55.x.x. No configuration matching. ↓

cause Using older ESLint version or missing flat config migration

fix

Update ESLint to >=8.56.0 and use eslint.config.js.

error Error: Cannot find module 'eslint-plugin-unicorn' ↓

cause Package not installed or missing in node_modules

fix

Run 'npm install --save-dev eslint eslint-plugin-unicorn'.

error TypeError: eslintPluginUnicorn is not a function ↓

cause Incorrectly importing default export in CommonJS

fix

Use 'const eslintPluginUnicorn = require('eslint-plugin-unicorn');' (no .default).

Warnings

breaking Minimum Node.js version is 18.18 starting from v60.0.0 ↓

fix Update Node.js to >=18.18 or pin eslint-plugin-unicorn to <60.0.0.

deprecated Rule 'no-array-push-push' renamed to 'prefer-single-call' in v59.0.0 ↓

fix Replace 'unicorn/no-array-push-push' with 'unicorn/prefer-single-call'.

deprecated Rule 'no-length-as-slice-end' renamed to 'no-unnecessary-slice-end' in v59.0.0 ↓

fix Replace 'unicorn/no-length-as-slice-end' with 'unicorn/no-unnecessary-slice-end'.

breaking ESLint <8.56.0 is no longer supported (flat config required starting v55?) ↓

fix Upgrade ESLint to >=8.56.0 and migrate to flat config (eslint.config.js).

gotcha Flat config (eslint.config.js) requires explicit import of plugin; global plugins no longer work ↓

fix Import the plugin in eslint.config.js as shown in the quickstart.

Install

npm install eslint-unicorn

yarn add eslint-unicorn

pnpm add eslint-unicorn

Imports

eslintPluginUnicorn
wrong
```
const eslintPluginUnicorn = require('eslint-plugin-unicorn').default;
```
correct
```
import eslintPluginUnicorn from 'eslint-plugin-unicorn';
```
Default export is the plugin object. In CommonJS, use `require('eslint-plugin-unicorn')` directly without .default.

configs.recommended

wrong

const { configs } = require('eslint-plugin-unicorn');

correct

import eslintPluginUnicorn from 'eslint-plugin-unicorn';
eslintPluginUnicorn.configs.recommended

Access recommended config via the default export. In CJS, use `require('eslint-plugin-unicorn').configs.recommended`.

rules

wrong

const rules = require('eslint-plugin-unicorn/rules');

correct

import eslintPluginUnicorn from 'eslint-plugin-unicorn';
eslintPluginUnicorn.rules['unicorn/better-regex']

Rules are accessed via the plugin object's 'rules' property. There is no separate 'rules' export.

Quickstart

Shows how to set up eslint-plugin-unicorn with flat config (ESLint >=8.56.0) using the recommended preset and additional rules.

import eslintPluginUnicorn from 'eslint-plugin-unicorn';
import globals from 'globals';

export default [
  eslintPluginUnicorn.configs.recommended,
  {
    languageOptions: {
      globals: globals.builtin,
    },
    plugins: {
      unicorn: eslintPluginUnicorn,
    },
    rules: {
      'unicorn/better-regex': 'error',
      'unicorn/catch-error-name': 'error',
    },
  },
];