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Configuring Vitest

Configuration

vitest will read your root vite.config.ts when it is present to match with the plugins and setup as your Vite app. If you want to have a different configuration for testing or your main app doesn't rely on Vite specifically, you could either:

Create vitest.config.ts, which will have the higher priority and will override the configuration from vite.config.ts
Pass --config option to CLI, e.g. vitest --config ./path/to/vitest.config.ts
Use process.env.VITEST or mode property on defineConfig (will be set to test/benchmark if not overridden) to conditionally apply different configuration in vite.config.ts

To configure vitest itself, add test property in your Vite config. You'll also need to add a reference to Vitest types using a triple slash command at the top of your config file, if you are importing defineConfig from vite itself.

using defineConfig from vite you should follow this:

/// <reference types="vitest" />
import { defineConfig } from 'vite'

export default defineConfig({
  test: {
    // ...
  },
})

using defineConfig from vitest/config you should follow this:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    // ...
  },
})

You can retrieve Vitest's default options to expand them if needed:

import { configDefaults, defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    exclude: [...configDefaults.exclude, 'packages/template/*'],
  },
})

When using a separate vitest.config.js, you can also extend Vite's options from another config file if needed:

import { defineConfig, mergeConfig } from 'vitest/config'
import viteConfig from './vite.config'

export default mergeConfig(viteConfig, defineConfig({
  test: {
    exclude: ['packages/template/*'],
  },
}))

::: warning mergeConfig helper is availabe in Vitest since v0.30.0. You can import it from vite directly, if you use lower version. :::

Options

:::tip In addition to the following options, you can also use any configuration option from Vite. For example, define to define global variables, or resolve.alias to define aliases. :::

::: tip All configuration options that are not supported inside a workspace project config have sign next to them. :::

include

Type: string[]
Default: ['**/*.{test,spec}.{js,mjs,cjs,ts,mts,cts,jsx,tsx}']

Files to include in the test run, using glob pattern.

exclude

Type: string[]
Default: ['**/node_modules/**', '**/dist/**', '**/cypress/**', '**/.{idea,git,cache,output,temp}/**', '**/{karma,rollup,webpack,vite,vitest,jest,ava,babel,nyc,cypress,tsup,build}.config.*']

Files to exclude from the test run, using glob pattern.

includeSource

Type: string[]
Default: []

Include globs for in-source test files.

When defined, Vitest will run all matched files with import.meta.vitest inside.

deps

Type: { external?, inline?, ... }

Handling for dependencies resolution.

deps.experimentalOptimizer

Type: DepOptimizationConfig & { enabled: boolean }
Version: Since Vitest 0.29.0
See also: Dep Optimization Options

Enable dependency optimization. If you have a lot of tests, this might improve their performance.

For jsdom and happy-dom environments, when Vitest will encounter the external library, it will be bundled into a single file using esbuild and imported as a whole module. This is good for several reasons:

Importing packages with a lot of imports is expensive. By bundling them into one file we can save a lot of time
Importing UI libraries is expensive because they are not meant to run inside Node.js
Your alias configuration is now respected inside bundled packages
Code in your tests is running closer to how it's running in the browser

Be aware that only packages in deps.experimentalOptimizer.include option are bundled (some plugins populate this automatically, like Svelte). You can read more about available options in Vite docs.

This options also inherits your optimizeDeps configuration. If you redefine include/exclude/entries option in deps.experimentalOptimizer it will overwrite your optimizeDeps when running tests.

::: tip You will not be able to edit your node_modules code for debugging, since the code is actually located in your cacheDir or test.cache.dir directory. If you want to debug with console.log statements, edit it directly or force rebundling with deps.experimentalOptimizer.force option. :::

deps.external

Type: (string | RegExp)[]
Default: ['**/node_modules/**']

Externalize means that Vite will bypass the package to native Node. Externalized dependencies will not be applied Vite's transformers and resolvers, so they do not support HMR on reload. Typically, packages under node_modules are externalized.

deps.inline

Type: (string | RegExp)[] | true
Default: []

Vite will process inlined modules. This could be helpful to handle packages that ship .js in ESM format (that Node can't handle).

If true, every dependency will be inlined. All dependencies, specified in ssr.noExternal will be inlined by default.

deps.fallbackCJS

Type boolean
Default: false

When a dependency is a valid ESM package, try to guess the cjs version based on the path. This might be helpful, if a dependency has the wrong ESM file.

This might potentially cause some misalignment if a package has different logic in ESM and CJS mode.

deps.registerNodeLoader

Type: boolean
Default: false

Use experimental Node loader to resolve imports inside externalized files, using Vite resolve algorithm.

If disabled, your alias and <plugin>.resolveId won't affect imports inside externalized packages (by default, node_modules).

deps.interopDefault

Type: boolean
Default: true

Interpret CJS module's default as named exports. Some dependencies only bundle CJS modules and don't use named exports that Node.js can statically analyze when a package is imported using import syntax instead of require. When importing such dependencies in Node environment using named exports, you will see this error:

import { read } from 'fs-jetpack';
         ^^^^
SyntaxError: Named export 'read' not found. The requested module 'fs-jetpack' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export.

Vitest doesn't do static analysis, and cannot fail before your running code, so you will most likely see this error when running tests, if this feature is disabled:

TypeError: createAsyncThunk is not a function
TypeError: default is not a function

By default, Vitest assumes you are using a bundler to bypass this and will not fail, but you can disable this behaviour manually, if you code is not processed.

deps.moduleDirectories

Type: string[]
Default: ['node_modules']

A list of directories that should be treated as module directories. This config option affects the behavior of vi.mock: when no factory is provided and the path of what you are mocking matches one of the moduleDirectories values, Vitest will try to resolve the mock by looking for a __mocks__ folder in the root of the project.

This option will also affect if a file should be treated as a module when externalizing dependencies. By default, Vitest imports external modules with native Node.js bypassing Vite transformation step.

Setting this option will override the default, if you wish to still search node_modules for packages include it along with any other options:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    deps: {
      moduleDirectories: ['node_modules', path.resolve('../../packages')],
    }
  },
})

runner

Type: VitestRunnerConstructor
Default: node, when running tests, or benchmark, when running benchmarks

Path to a custom test runner. This is an advanced feature and should be used with custom library runners. You can read more about it in the documentation.

benchmark

Type: { include?, exclude?, ... }

Options used when running vitest bench.

benchmark.include

Type: string[]
Default: ['**/*.{bench,benchmark}.{js,mjs,cjs,ts,mts,cts,jsx,tsx}']

Include globs for benchmark test files

benchmark.exclude

Type: string[]
Default: ['node_modules', 'dist', '.idea', '.git', '.cache']

Exclude globs for benchmark test files

benchmark.includeSource

Type: string[]
Default: []

Include globs for in-source benchmark test files. This option is similar to includeSource.

When defined, Vitest will run all matched files with import.meta.vitest inside.

benchmark.reporters

Type: Arrayable<BenchmarkBuiltinReporters | Reporter>
Default: 'default'

Custom reporter for output. Can contain one or more built-in report names, reporter instances, and/or paths to custom reporters.

benchmark.outputFile

Type: string | Record<string, string>

Write benchmark results to a file when the --reporter=json option is also specified. By providing an object instead of a string you can define individual outputs when using multiple reporters.

To provide object via CLI command, use the following syntax: --outputFile.json=./path --outputFile.junit=./other-path.

alias

Type: Record<string, string> | Array<{ find: string | RegExp, replacement: string, customResolver?: ResolverFunction | ResolverObject }>

Define custom aliases when running inside tests. They will be merged with aliases from resolve.alias.

globals

Type: boolean
Default: false
CLI: --globals, --globals=false

By default, vitest does not provide global APIs for explicitness. If you prefer to use the APIs globally like Jest, you can pass the --globals option to CLI or add globals: true in the config.

// vite.config.ts
import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    globals: true,
  },
})

To get TypeScript working with the global APIs, add vitest/globals to the types field in your tsconfig.json

// tsconfig.json
{
  "compilerOptions": {
    "types": ["vitest/globals"]
  }
}

If you are already using unplugin-auto-import in your project, you can also use it directly for auto importing those APIs.

// vite.config.ts
import { defineConfig } from 'vitest/config'
import AutoImport from 'unplugin-auto-import/vite'

export default defineConfig({
  plugins: [
    AutoImport({
      imports: ['vitest'],
      dts: true, // generate TypeScript declaration
    }),
  ],
})

environment

Type: 'node' | 'jsdom' | 'happy-dom' | 'edge-runtime' | string
Default: 'node'
CLI: --environment=<env>

The environment that will be used for testing. The default environment in Vitest is a Node.js environment. If you are building a web application, you can use browser-like environment through either jsdom or happy-dom instead. If you are building edge functions, you can use edge-runtime environment

By adding a @vitest-environment docblock or comment at the top of the file, you can specify another environment to be used for all tests in that file:

Docblock style:

/**
 * @vitest-environment jsdom
 */

test('use jsdom in this test file', () => {
  const element = document.createElement('div')
  expect(element).not.toBeNull()
})

Comment style:

// @vitest-environment happy-dom

test('use happy-dom in this test file', () => {
  const element = document.createElement('div')
  expect(element).not.toBeNull()
})

For compatibility with Jest, there is also a @jest-environment:

/**
 * @jest-environment jsdom
 */

test('use jsdom in this test file', () => {
  const element = document.createElement('div')
  expect(element).not.toBeNull()
})

If you are running Vitest with --threads=false flag, your tests will be run in this order: node, jsdom, happy-dom, edge-runtime, custom environments. Meaning, that every test with the same environment is grouped together, but is still running sequentially.

Starting from 0.23.0, you can also define custom environment. When non-builtin environment is used, Vitest will try to load package vitest-environment-${name}. That package should export an object with the shape of Environment:

import type { Environment } from 'vitest'

export default <Environment>{
  name: 'custom',
  setup() {
    // custom setup
    return {
      teardown() {
        // called after all tests with this env have been run
      }
    }
  }
}

Vitest also exposes builtinEnvironments through vitest/environments entry, in case you just want to extend it. You can read more about extending environments in our guide.

environmentOptions

Type: Record<'jsdom' | string, unknown>
Default: {}

These options are passed down to setup method of current environment. By default, you can configure only JSDOM options, if you are using it as your test environment.

environmentMatchGlobs

Type: [string, EnvironmentName][]
Default: []

Automatically assign environment based on globs. The first match will be used.

For example:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    environmentMatchGlobs: [
      // all tests in tests/dom will run in jsdom
      ['tests/dom/**', 'jsdom'],
      // all tests in tests/ with .edge.test.ts will run in edge-runtime
      ['**\/*.edge.test.ts', 'edge-runtime'],
      // ...
    ]
  }
})

poolMatchGlobs

Type: [string, 'browser' | 'threads' | 'child_process'][]
Default: []
Version: Since Vitest 0.29.4

Automatically assign pool in which tests will run based on globs. The first match will be used.

For example:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    poolMatchGlobs: [
      // all tests in "worker-specific" directory will run inside a worker as if you enabled `--threads` for them,
      ['**/tests/worker-specific/**', 'threads'],
      // run all tests in "browser" directory in an actual browser
      ['**/tests/browser/**', 'browser'],
      // all other tests will run based on "browser.enabled" and "threads" options, if you didn't specify other globs
      // ...
    ]
  }
})

update

Type: boolean
Default: false
CLI: -u, --update, --update=false

Update snapshot files. This will update all changed snapshots and delete obsolete ones.

watch

Type: boolean
Default: true
CLI: -w, --watch, --watch=false

Enable watch mode

root

Type: string
CLI: -r <path>, --root=<path>

Project root

reporters

Type: Reporter | Reporter[]
Default: 'default'
CLI: --reporter=<name>, --reporter=<name1> --reporter=<name2>

Custom reporters for output. Reporters can be a Reporter instance or a string to select built in reporters:

'default' - collapse suites when they pass
'basic' - give a reporter like default reporter in ci
'verbose' - keep the full task tree visible
'dot' - show each task as a single dot
'junit' - JUnit XML reporter (you can configure testsuites tag name with VITEST_JUNIT_SUITE_NAME environmental variable)
'json' - give a simple JSON summary
'html' - outputs HTML report based on @vitest/ui
'hanging-process' - displays a list of hanging processes, if Vitest cannot exit process safely. This might be a heavy operation, enable it only if Vitest consistently cannot exit process
path of a custom reporter (e.g. './path/to/reporter.ts', '@scope/reporter')

outputFile

Type: string | Record<string, string>
CLI: --outputFile=<path>, --outputFile.json=./path

Write test results to a file when the --reporter=json, --reporter=html or --reporter=junit option is also specified. By providing an object instead of a string you can define individual outputs when using multiple reporters.

threads

Type: boolean
Default: true
CLI: --threads, --threads=false

Enable multi-threading using tinypool (a lightweight fork of Piscina). Prior to Vitest 0.29.0, Vitest was still running tests inside worker thread, even if this option was disabled. Since 0.29.0, if this option is disabled, Vitest uses child_process to spawn a process to run tests inside, meaning you can use process.chdir and other API that was not available inside workers. If you want to revert to the previous behaviour, use --single-thread option instead.

Disabling this option also disables module isolation, meaning all tests with the same environment are running inside a single child process.

singleThread

Type: boolean
Default: false
Version: Since Vitest 0.29.0

Run all tests with the same environment inside a single worker thread. This will disable built-in module isolation (your source code or inlined code will still be reevaluated for each test), but can improve test performance. Before Vitest 0.29.0 this was equivalent to using --no-threads.

:::warning Even though this option will force tests to run one after another, this option is different from Jest's --runInBand. Vitest uses workers not only for running tests in parallel, but also to provide isolation. By disabling this option, your tests will run sequentially, but in the same global context, so you must provide isolation yourself.

This might cause all sorts of issues, if you are relying on global state (frontend frameworks usually do) or your code relies on environment to be defined separately for each test. But can be a speed boost for your tests (up to 3 times faster), that don't necessarily rely on global state or can easily bypass that. :::

maxThreads

Type: number
Default: available CPUs

Maximum number of threads. You can also use VITEST_MAX_THREADS environment variable.

minThreads

Type: number
Default: available CPUs

Minimum number of threads. You can also use VITEST_MIN_THREADS environment variable.

useAtomics

Type: boolean
Default: false
Version: Since Vitest 0.28.3

Use Atomics to synchronize threads.

This can improve performance in some cases, but might cause segfault in older Node versions.

testTimeout

Type: number
Default: 5000
CLI: --test-timeout=5000

Default timeout of a test in milliseconds

hookTimeout

Type: number
Default: 10000

Default timeout of a hook in milliseconds

teardownTimeout

Type: number
Default: 10000

Default timeout to wait for close when Vitest shuts down, in milliseconds

silent

Type: boolean
Default: false
CLI: --silent, --silent=false

Silent console output from tests

setupFiles

Type: string | string[]

Path to setup files. They will be run before each test file.

:::info Changing setup files will trigger rerun of all tests. :::

You can use process.env.VITEST_POOL_ID (integer-like string) inside to distinguish between threads (will always be '1', if run with threads: false).

:::tip Note, that if you are running --threads=false, this setup file will be run in the same global scope multiple times. Meaning, that you are accessing the same global object before each test, so make sure you are not doing the same thing more than you need. :::

For example, you may rely on a global variable:

import { config } from '@some-testing-lib'

if (!globalThis.defined) {
  config.plugins = [myCoolPlugin]
  computeHeavyThing()
  globalThis.defined = true
}

// hooks are reset before each suite
afterEach(() => {
  cleanup()
})

globalThis.resetBeforeEachTest = true

globalSetup

Type: string | string[]

Path to global setup files, relative to project root

A global setup file can either export named functions setup and teardown or a default function that returns a teardown function (example).

::: info Multiple globalSetup files are possible. setup and teardown are executed sequentially with teardown in reverse order. :::

::: warning Beware that the global setup is run in a different global scope, so your tests don't have access to variables defined here. :::

watchExclude

Type: string[]
Default: ['**/node_modules/**', '**/dist/**']

Glob pattern of file paths to be ignored from triggering watch rerun.

forceRerunTriggers

Type: string[]
Default: ['**/package.json/**', '**/vitest.config.*/**', '**/vite.config.*/**']

Glob pattern of file paths that will trigger the whole suite rerun. When paired with the --changed argument will run the whole test suite if the trigger is found in the git diff.

Useful if you are testing calling CLI commands, because Vite cannot construct a module graph:

test('execute a script', async () => {
  // Vitest cannot rerun this test, if content of `dist/index.js` changes
  await execa('node', ['dist/index.js'])
})

::: tip Make sure that your files are not excluded by watchExclude. :::

isolate

Type: boolean
Default: true
CLI: --isolate, --isolate=false

Isolate environment for each test file. Does not work if you disable --threads.

coverage

You can use c8, istanbul or a custom coverage solution for coverage collection.

You can provide coverage options to CLI with dot notation:

npx vitest --coverage.enabled --coverage.provider=istanbul --coverage.all

::: warning If you are using coverage options with dot notation, don't forget to specify --coverage.enabled. Do not provide a single --coverage option in that case. :::

coverage.provider

Type: 'c8' | 'istanbul' | 'custom'
Default: 'c8'
CLI: --coverage.provider=<provider>

Use provider to select the tool for coverage collection.

coverage.enabled

Type: boolean
Default: false
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.enabled, --coverage.enabled=false

Enables coverage collection. Can be overridden using --coverage CLI option.

coverage.include

Type: string[]
Default: ['**']
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.include=<path>, --coverage.include=<path1> --coverage.include=<path2>

List of files included in coverage as glob patterns

coverage.extension

Type: string | string[]
Default: ['.js', '.cjs', '.mjs', '.ts', '.mts', '.cts', '.tsx', '.jsx', '.vue', '.svelte']
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.extension=<extension>, --coverage.extension=<extension1> --coverage.extension=<extension2>

coverage.exclude

Type: string[]
Default:

[
  'coverage/**',
  'dist/**',
  'packages/*/test{,s}/**',
  '**/*.d.ts',
  'cypress/**',
  'test{,s}/**',
  'test{,-*}.{js,cjs,mjs,ts,tsx,jsx}',
  '**/*{.,-}test.{js,cjs,mjs,ts,tsx,jsx}',
  '**/*{.,-}spec.{js,cjs,mjs,ts,tsx,jsx}',
  '**/__tests__/**',
  '**/{karma,rollup,webpack,vite,vitest,jest,ava,babel,nyc,cypress,tsup,build}.config.*',
  '**/.{eslint,mocha,prettier}rc.{js,cjs,yml}',
]

Available for providers: 'c8' | 'istanbul'
CLI: --coverage.exclude=<path>, --coverage.exclude=<path1> --coverage.exclude=<path2>

List of files excluded from coverage as glob patterns.

coverage.all

Type: boolean
Default: false
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.all, --coverage.all=false

Whether to include all files, including the untested ones into report.

coverage.clean

Type: boolean
Default: true
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.clean, --coverage.clean=false

Clean coverage results before running tests

coverage.cleanOnRerun

Type: boolean
Default: true
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.cleanOnRerun, --coverage.cleanOnRerun=false

Clean coverage report on watch rerun

coverage.reportsDirectory

Type: string
Default: './coverage'
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.reportsDirectory=<path>

Directory to write coverage report to.

coverage.reporter

Type: string | string[] | [string, {}][]
Default: ['text', 'html', 'clover', 'json']
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.reporter=<reporter>, --coverage.reporter=<reporter1> --coverage.reporter=<reporter2>

Coverage reporters to use. See istanbul documentation for detailed list of all reporters. See @types/istanbul-reporter for details about reporter specific options.

The reporter has three different types:

A single reporter: { reporter: 'html' }
Multiple reporters without options: { reporter: ['html', 'json'] }

A single or multiple reporters with reporter options:

{
  reporter: [
    ['lcov', { 'projectRoot': './src' }],
    ['json', { 'file': 'coverage.json' }],
    ['text']
  ]
}

Since Vitest 0.31.0, you can check your coverage report in Vitest UI: check Vitest UI Coverage for more details.

coverage.reportOnFailure

Type: boolean
Default: true
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.reportOnFailure, --coverage.reportOnFailure=false
Version: Since Vitest 0.31.2

Generate coverage report even when tests fail.

coverage.skipFull

Type: boolean
Default: false
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.skipFull, --coverage.skipFull=false

Do not show files with 100% statement, branch, and function coverage.

coverage.perFile

Type: boolean
Default: false
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.perFile, --coverage.perFile=false

Check thresholds per file. See lines, functions, branches and statements for the actual thresholds.

coverage.thresholdAutoUpdate

Type: boolean
Default: false
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.thresholdAutoUpdate=<boolean>

Update threshold values lines, functions, branches and statements to configuration file when current coverage is above the configured thresholds. This option helps to maintain thresholds when coverage is improved.

coverage.lines

Type: number
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.lines=<number>

Threshold for lines. See istanbul documentation for more information.

coverage.functions

Type: number
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.functions=<number>

Threshold for functions. See istanbul documentation for more information.

coverage.branches

Type: number
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.branches=<number>

Threshold for branches. See istanbul documentation for more information.

coverage.statements

Type: number
Available for providers: 'c8' | 'istanbul'
CLI: --coverage.statements=<number>

Threshold for statements. See istanbul documentation for more information.

coverage.allowExternal

Type: boolean
Default: false
Available for providers: 'c8'
CLI: --coverage.allowExternal, --coverage.allowExternal=false

Allow files from outside of your cwd.

coverage.excludeNodeModules

Type: boolean
Default: true
Available for providers: 'c8'
CLI: --coverage.excludeNodeModules, --coverage.excludeNodeModules=false

Exclude coverage under /node_modules/.

coverage.src

Type: string[]
Default: process.cwd()
Available for providers: 'c8'
CLI: --coverage.src=<path>

Specifies the directories that are used when --all is enabled.

coverage.100

Type: boolean
Default: false
Available for providers: 'c8'
CLI: --coverage.100, --coverage.100=false

Shortcut for --check-coverage --lines 100 --functions 100 --branches 100 --statements 100.

coverage.ignoreClassMethods

Type: string[]
Default: []
Available for providers: 'istanbul'
CLI: --coverage.ignoreClassMethods=<method>

Set to array of class method names to ignore for coverage. See istanbul documentation for more information.

coverage.watermarks

Type:

{
  statements?: [number, number],
  functions?: [number, number],
  branches?: [number, number],
  lines?: [number, number]
}

Default:

{
  statements: [50, 80],
  functions: [50, 80],
  branches: [50, 80],
  lines: [50, 80]
}

Available for providers: 'c8' | 'istanbul'

Watermarks for statements, lines, branches and functions. See istanbul documentation for more information.

coverage.customProviderModule

Type: string
Available for providers: 'custom'
CLI: --coverage.customProviderModule=<path or module name>

Specifies the module name or path for the custom coverage provider module. See Guide - Custom Coverage Provider for more information.

testNamePattern

Type string | RegExp
CLI: -t <pattern>, --testNamePattern=<pattern>, --test-name-pattern=<pattern>

Run tests with full names matching the pattern. If you add OnlyRunThis to this property, tests not containing the word OnlyRunThis in the test name will be skipped.

import { expect, test } from 'vitest'

// run
test('OnlyRunThis', () => {
  expect(true).toBe(true)
})

// skipped
test('doNotRun', () => {
  expect(true).toBe(true)
})

open

Type: boolean
Default: false
CLI: --open, --open=false

Open Vitest UI (WIP)

api

Type: boolean | number
Default: false
CLI: --api, --api.port, --api.host, --api.strictPort

Listen to port and serve API. When set to true, the default port is 51204

browser

Type: { enabled?, name?, provider?, headless?, api?, slowHijackESM? }
Default: { enabled: false, headless: process.env.CI, api: 63315 }
Version: Since Vitest 0.29.4
CLI: --browser, --browser=<name>, --browser.name=chrome --browser.headless

Run Vitest tests in a browser. We use WebdriverIO for running tests by default, but it can be configured with browser.provider option.

::: tip NOTE Read more about testing in a real browser in the guide page. :::

::: warning This is an experimental feature. Breaking changes might not follow semver, please pin Vitest's version when using it. :::

browser.enabled

Type: boolean
Default: false
CLI: --browser, --browser.enabled=false

Run all tests inside a browser by default. Can be overriden with poolMatchGlobs option.

browser.name

Type: string
CLI: --browser=safari

Run all tests in a specific browser. Possible options in different providers:

webdriverio: firefox, chrome, edge, safari
playwright: firefox, webkit, chromium
custom: any string that will be passed to the provider

browser.headless

Type: boolean
Default: process.env.CI
CLI: --browser.headless, --brower.headless=false

Run the browser in a headless mode. If you are running Vitest in CI, it will be enabled by default.

browser.api

Type: number | { port?, strictPort?, host? }
Default: 63315
CLI: --browser.api=63315, --browser.api.port=1234, --browser.api.host=example.com

Configure options for Vite server that serves code in the browser. Does not affect test.api option.

browser.provider

Type: 'webdriverio' | 'playwright' | string
Default: 'webdriverio'
CLI: --browser.provider=playwright

Path to a provider that will be used when running browser tests. Vitest provides two providers which are webdriverio (default) and playwright. Custom providers should be exported using default export and have this shape:

export interface BrowserProvider {
  name: string
  getSupportedBrowsers(): readonly string[]
  initialize(ctx: Vitest, options: { browser: string }): Awaitable<void>
  openPage(url: string): Awaitable<void>
  close(): Awaitable<void>
}

::: warning This is an advanced API for library authors. If you just need to run tests in a browser, use the browser option. :::

browser.slowHijackESM

Type: boolean
Default: true
Version: Since Vitest 0.31.0

When running tests in Node.js Vitest can use its own module resolution to easily mock modules with vi.mock syntax. However it's not so easy to replicate ES module resolution in browser, so we need to transform your source files before browser can consume it.

This option has no effect on tests running inside Node.js.

This options is enabled by default when running in the browser. If you don't rely on spying on ES modules with vi.spyOn and don't use vi.mock, you can disable this to get a slight boost to performance.

clearMocks

Type: boolean
Default: false

Will call .mockClear() on all spies before each test. This will clear mock history, but not reset its implementation to the default one.

mockReset

Type: boolean
Default: false

Will call .mockReset() on all spies before each test. This will clear mock history and reset its implementation to an empty function (will return undefined).

restoreMocks

Type: boolean
Default: false

Will call .mockRestore() on all spies before each test. This will clear mock history and reset its implementation to the original one.

unstubEnvs

Type: boolean
Default: false
Version: Since Vitest 0.26.0

Will call vi.unstubAllEnvs before each test.

unstubGlobals

Type: boolean
Default: false
Version: Since Vitest 0.26.0

Will call vi.unstubAllGlobals before each test.

transformMode

Type: { web?, ssr? }

Determine the transform method of modules

transformMode.ssr

Type: RegExp[]
Default: [/\.([cm]?[jt]sx?|json)$/]

Use SSR transform pipeline for the specified files.
Vite plugins will receive ssr: true flag when processing those files.

transformMode.web

Type: RegExp[]
Default: modules other than those specified in transformMode.ssr

First do a normal transform pipeline (targeting browser), then do a SSR rewrite to run the code in Node.
Vite plugins will receive ssr: false flag when processing those files.

When you use JSX as component models other than React (e.g. Vue JSX or SolidJS), you might want to config as following to make .tsx / .jsx transformed as client-side components:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    transformMode: {
      web: [/\.[jt]sx$/],
    },
  },
})

snapshotFormat

Type: PrettyFormatOptions

Format options for snapshot testing. These options are passed down to pretty-format.

resolveSnapshotPath

Type: (testPath: string, snapExtension: string) => string
Default: stores snapshot files in __snapshots__ directory

Overrides default snapshot path. For example, to store snapshots next to test files:

import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    resolveSnapshotPath: (testPath, snapExtension) => testPath + snapExtension,
  },
})

allowOnly

Type: boolean
Default: false
CLI: --allowOnly, --allowOnly=false

Allow tests and suites that are marked as only.

dangerouslyIgnoreUnhandledErrors

Type: boolean
Default: false
CLI: --dangerouslyIgnoreUnhandledErrors --dangerouslyIgnoreUnhandledErrors=false

Ignore any unhandled errors that occur.

passWithNoTests

Type: boolean
Default: false
CLI: --passWithNoTests, --passWithNoTests=false

Vitest will not fail, if no tests will be found.

logHeapUsage

Type: boolean
Default: false
CLI: --logHeapUsage, --logHeapUsage=false

Show heap usage after each test. Useful for debugging memory leaks.

css

Type: boolean | { include?, exclude?, modules? }

Configure if CSS should be processed. When excluded, CSS files will be replaced with empty strings to bypass the subsequent processing. CSS Modules will return a proxy to not affect runtime.

css.include

Type: RegExp | RegExp[]
Default: []

RegExp pattern for files that should return actual CSS and will be processed by Vite pipeline.

:::tip To process all CSS files, use /.+/. :::

css.exclude

Type: RegExp | RegExp[]
Default: []

RegExp pattern for files that will return an empty CSS file.

css.modules

Type: { classNameStrategy? }
Default: {}

css.modules.classNameStrategy

Type: 'stable' | 'scoped' | 'non-scoped'
Default: 'stable'

If you decide to process CSS files, you can configure if class names inside CSS modules should be scoped. You can choose one of the options:

stable: class names will be generated as _${name}_${hashedFilename}, which means that generated class will stay the same, if CSS content is changed, but will change, if the name of the file is modified, or file is moved to another folder. This setting is useful, if you use snapshot feature.
scoped: class names will be generated as usual, respecting css.modules.generateScopeName method, if you have one and CSS processing is enabled. By default, filename will be generated as _${name}_${hash}, where hash includes filename and content of the file.
non-scoped: class names will not be hashed.

::: warning By default, Vitest exports a proxy, bypassing CSS Modules processing. If you rely on CSS properties on your classes, you have to enable CSS processing using include option. :::

maxConcurrency

Type: number
Default: 5

A number of tests that are allowed to run at the same time marked with test.concurrent.

Test above this limit will be queued to run when available slot appears.

cache

Type: false | { dir? }

Options to configure Vitest cache policy. At the moment Vitest stores cache for test results to run the longer and failed tests first.

cache.dir

Type: string
Default: node_modules/.vitest

Path to cache directory.

sequence

Type: { sequencer?, shuffle?, seed?, hooks?, setupFiles? }

Options for how tests should be sorted.

You can provide sequence options to CLI with dot notation:

npx vitest --sequence.shuffle --sequence.seed=1000

sequence.sequencer

Type: TestSequencerConstructor
Default: BaseSequencer

A custom class that defines methods for sharding and sorting. You can extend BaseSequencer from vitest/node, if you only need to redefine one of the sort and shard methods, but both should exist.

Sharding is happening before sorting, and only if --shard option is provided.

sequence.shuffle

Type: boolean
Default: false
CLI: --sequence.shuffle, --sequence.shuffle=false

If you want tests to run randomly, you can enable it with this option, or CLI argument --sequence.shuffle.

Vitest usually uses cache to sort tests, so long running tests start earlier - this makes tests run faster. If your tests will run in random order you will lose this performance improvement, but it may be useful to track tests that accidentally depend on another run previously.

sequence.seed

Type: number
Default: Date.now()
CLI: --sequence.seed=1000

Sets the randomization seed, if tests are running in random order.

sequence.hooks

Type: 'stack' | 'list' | 'parallel'
Default: 'parallel'
CLI: --sequence.hooks=<value>

Changes the order in which hooks are executed.

stack will order "after" hooks in reverse order, "before" hooks will run in the order they were defined
list will order all hooks in the order they are defined
parallel will run hooks in a single group in parallel (hooks in parent suites will still run before the current suite's hooks)

sequence.setupFiles

Type: 'list' | 'parallel'
Default: 'parallel'
CLI: --sequence.setupFiles=<value>
Version: Since Vitest 0.29.3

Changes the order in which setup files are executed.

list will run setup files in the order they are defined
parallel will run setup files in parallel

typecheck

Options for configuring typechecking test environment.

typecheck.checker

Type: 'tsc' | 'vue-tsc' | string
Default: tsc

What tools to use for type checking. Vitest will spawn a process with certain parameters for easier parsing, depending on the type. Checker should implement the same output format as tsc.

You need to have a package installed to use typechecker:

tsc requires typescript package
vue-tsc requires vue-tsc package

You can also pass down a path to custom binary or command name that produces the same output as tsc --noEmit --pretty false.

typecheck.include

Type: string[]
Default: ['**/*.{test,spec}-d.{ts,js}']

Glob pattern for files that should be treated as test files

typecheck.exclude

Type: string[]
Default: ['**/node_modules/**', '**/dist/**', '**/cypress/**', '**/.{idea,git,cache,output,temp}/**']

Glob pattern for files that should not be treated as test files

typecheck.allowJs

Type: boolean
Default: false

Check JS files that have @ts-check comment. If you have it enabled in tsconfig, this will not overwrite it.

typecheck.ignoreSourceErrors

Type: boolean
Default: false

Do not fail, if Vitest found errors outside the test files. This will not show you non-test errors at all.

By default, if Vitest finds source error, it will fail test suite.

typecheck.tsconfig

Type: string
Default: tries to find closest tsconfig.json

Path to custom tsconfig, relative to the project root.

slowTestThreshold

Type: number
Default: 300

The number of milliseconds after which a test is considered slow and reported as such in the results.

chaiConfig

Type: { includeStack?, showDiff?, truncateThreshold? }
Default: { includeStack: false, showDiff: true, truncateThreshold: 40 }
Version: Since Vitest 0.30.0

Equivalent to Chai config.

chaiConfig.includeStack

Type: boolean
Default: false

Influences whether stack trace is included in Assertion error message. Default of false suppresses stack trace in the error message.

chaiConfig.showDiff

Type: boolean
Default: true

Influences whether or not the showDiff flag should be included in the thrown AssertionErrors. false will always be false; true will be true when the assertion has requested a diff to be shown.

chaiConfig.truncateThreshold

Type: number
Default: 40

Sets length threshold for actual and expected values in assertion errors. If this threshold is exceeded, for example for large data structures, the value is replaced with something like [ Array(3) ] or { Object (prop1, prop2) }. Set it to 0 if you want to disable truncating altogether.

This config option affects truncating values in test.each titles and inside the assertion error message.

bail

Type: number
Default: 0
CLI: --bail=<value>
Version: Since Vitest 0.31.0

Stop test execution when given number of tests have failed.

By default Vitest will run all of your test cases even if some of them fail. This may not be desired for CI builds where you are only interested in 100% successful builds and would like to stop test execution as early as possible when test failures occur. The bail option can be used to speed up CI runs by preventing it from running more tests when failures have occured.

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