eslint-plugin-jest-extended

ESLint plugin for Jest Extended

Installation

$ yarn add --dev eslint eslint-plugin-jest-extended

Note: If you installed ESLint globally then you must also install eslint-plugin-jest-extended globally.

Usage

Note

eslint.config.js is supported, though most of the plugin documentation still currently uses .eslintrc syntax.

Refer to the ESLint documentation on the new configuration file format for more.

Add jest-extended to the plugins section of your .eslintrc configuration file. You can omit the eslint-plugin- prefix:

{
  "plugins": ["jest-extended"]
}

Then configure the rules you want to use under the rules section.

{
  "rules": {
    "jest-extended/prefer-to-be-true": "warn",
    "jest-extended/prefer-to-be-false": "error"
  }
}

Shareable configurations

Recommended

This plugin does not export a recommended configuration, as the rules provided by this plugin are about enforcing usage of preferred matchers for particular patterns, rather than helping to prevent bugs & commonly overlooked traps.

All

If you want to enable all rules instead of only some you can do so by adding the all configuration to your .eslintrc config file:

{
  "extends": ["plugin:jest-extended/all"]
}

To enable this configuration with eslint.config.js, use jestExtended.configs['flat/all']:

const jestExtended = require('eslint-plugin-jest-extended');

module.exports = [
  {
    files: [
      /* glob matching your test files */
    ],
    ...jestExtended.configs['flat/all'],
  },
];

Note that the all configuration may change in any release and is thus unsuited for installations requiring long-term consistency.

Rules

🔧 Automatically fixable by the --fix CLI option.

Name	Description	🔧
prefer-to-be-array	Suggest using toBeArray()	🔧
prefer-to-be-false	Suggest using toBeFalse()	🔧
prefer-to-be-object	Suggest using toBeObject()	🔧
prefer-to-be-true	Suggest using toBeTrue()	🔧
prefer-to-have-been-called-once	Suggest using toHaveBeenCalledOnce()	🔧

Credit

• eslint-plugin-jest

Related Projects

eslint-plugin-jest

This project aims to provide linting rules to aid in writing tests using jest.

https://github.com/jest-community/eslint-plugin-jest

eslint-plugin-jest-formatting

This project aims to provide formatting rules (auto-fixable where possible) to ensure consistency and readability in jest test suites.

https://github.com/dangreenisrael/eslint-plugin-jest-formatting