README.md

eslint-plugin-vitest

ESLint plugin for Vitest

Installation

You'll first need to install ESLint:

npm i eslint --save-dev

Next, install @vitest/eslint-plugin

npm install @vitest/eslint-plugin --save-dev

Usage

Make sure you're running ESLint v9.0.0 or higher for the latest version of this plugin to work. The following example is how your eslint.config.js should be setup for this plugin to work for you.

import vitest from "@vitest/eslint-plugin";

export default [
  {
    files: ["tests/**"], // or any other pattern
    plugins: {
      vitest
    },
    rules: {
      ...vitest.configs.recommended.rules, // you can also use vitest.configs.all.rules to enable all rules
      "vitest/max-nested-describe": ["error", { "max": 3 }] // you can also modify rules' behavior using option like this
    },
  },
];

If you're not using the latest version of ESLint (version v8.57.0 or lower) you can setup this plugin using the following configuration

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

{
  "plugins": ["@vitest"]
}

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

{
  "rules": {
    "vitest/max-nested-describe": [
      "error",
      {
        "max": 3
      }
    ]
  }
}

If you're using old ESLint configuration, make sure to use legacy key like the following

{
  "extends": ["plugin:@vitest/legacy-recommended"] // or legacy-all
}

Enabling with type-testing

Vitest ships with an optional type-testing feature, which is disabled by default.

If you're using this feature, you should also enabled typecheck in the settings for this plugin. This ensures that rules like expect-expect account for type-related assertions in tests.

import vitest from "@vitest/eslint-plugin";

export default [
  {
    files: ["tests/**"], // or any other pattern
    plugins: {
      vitest,
    },
    rules: {
      ...vitest.configs.recommended.rules,
    },
   settings: {
      vitest: {
        typecheck: true
      }
    },
    languageOptions: {
      globals: {
        ...vitest.environments.env.globals,
      },
    },
  },
]

Shareable configurations

Recommended

This plugin exports a recommended configuration that enforces good testing practices.

To enable this configuration with eslint.config.js, use vitest.configs.recommended:

import vitest from "@vitest/eslint-plugin";

export default [
  {
    files: ["tests/**"], // or any other pattern
     ...vitest.configs.recommended,
  }
]

All

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

import vitest from "@vitest/eslint-plugin";

export default [
  {
    files: ["tests/**"], // or any other pattern
     ...vitest.configs.all,
  }
]

Rules

💼 Configurations enabled in.
⚠️ Configurations set to warn in.
✅ Set in the recommended configuration.
🔧 Automatically fixable by the --fix CLI option.
💡 Manually fixable by editor suggestions.
❌ Deprecated.

Name	Description	💼	⚠️	🔧	💡	❌
consistent-test-filename	require .spec test file pattern
consistent-test-it	enforce using test or it but not both			🔧
expect-expect	enforce having expectation in test body	✅
max-expects	enforce a maximum number of expect per test
max-nested-describe	require describe block to be less than set max value or default value
no-alias-methods	disallow alias methods			🔧
no-commented-out-tests	disallow commented out tests	✅
no-conditional-expect	disallow conditional expects
no-conditional-in-test	disallow conditional tests
no-conditional-tests	disallow conditional tests
no-disabled-tests	disallow disabled tests
no-done-callback	disallow using a callback in asynchronous tests and hooks				💡	❌
no-duplicate-hooks	disallow duplicate hooks and teardown hooks
no-focused-tests	disallow focused tests			🔧
no-hooks	disallow setup and teardown hooks
no-identical-title	disallow identical titles	✅		🔧
no-import-node-test	disallow importing node:test	✅		🔧
no-interpolation-in-snapshots	disallow string interpolation in snapshots			🔧
no-large-snapshots	disallow large snapshots
no-mocks-import	disallow importing from mocks directory
no-restricted-matchers	disallow the use of certain matchers
no-restricted-vi-methods	disallow specific vi. methods
no-standalone-expect	disallow using expect outside of it or test blocks
no-test-prefixes	disallow using test as a prefix			🔧
no-test-return-statement	disallow return statements in tests
prefer-called-with	enforce using toBeCalledWith() or toHaveBeenCalledWith()			🔧
prefer-comparison-matcher	enforce using the built-in comparison matchers			🔧
prefer-each	enforce using each rather than manual loops
prefer-equality-matcher	enforce using the built-in quality matchers				💡
prefer-expect-assertions	enforce using expect assertions instead of callbacks				💡
prefer-expect-resolves	enforce using expect().resolves over expect(await ...) syntax			🔧
prefer-hooks-in-order	enforce having hooks in consistent order
prefer-hooks-on-top	enforce having hooks before any test cases
prefer-lowercase-title	enforce lowercase titles			🔧
prefer-mock-promise-shorthand	enforce mock resolved/rejected shorthands for promises			🔧
prefer-snapshot-hint	enforce including a hint with external snapshots
prefer-spy-on	enforce using vi.spyOn			🔧
prefer-strict-equal	enforce strict equal over equal				💡
prefer-to-be	enforce using toBe()			🔧
prefer-to-be-falsy	enforce using toBeFalsy()			🔧
prefer-to-be-object	enforce using toBeObject()			🔧
prefer-to-be-truthy	enforce using toBeTruthy			🔧
prefer-to-contain	enforce using toContain()			🔧
prefer-to-have-length	enforce using toHaveLength()			🔧
prefer-todo	enforce using test.todo			🔧
prefer-vi-mocked	Prefer vi.mocked() over fn as Mock			🔧
require-hook	require setup and teardown to be within a hook
require-local-test-context-for-concurrent-snapshots	require local Test Context for concurrent snapshot tests	✅
require-to-throw-message	require toThrow() to be called with an error message
require-top-level-describe	enforce that all tests are in a top-level describe
valid-describe-callback	enforce valid describe callback	✅
valid-expect	enforce valid expect() usage	✅		🔧
valid-title	enforce valid titles	✅		🔧

Credits

• eslint-plugin-jest Most of the rules in this plugin are essentially ports of Jest plugin rules with minor modifications

Licence

MIT Licence © 2022 - present veritem and contributors