vitest/docs/guide/environment.md

Test Environment

Vitest provides environment option to run code inside a specific environment. You can modify how environment behaves with environmentOptions option.

By default, you can use these environments:

• node is default environment
• jsdom emulates browser environment by providing Browser API, uses jsdom package
• happy-dom emulates browser environment by providing Browser API, and considered to be faster than jsdom, but lacks some API, uses happy-dom package
• edge-runtime emulates Vercel's edge-runtime, uses @edge-runtime/vm package

Starting from 0.23.0, you can create your own package to extend Vitest environment. To do so, create package with the name 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
      }
    }
  }
}

You also have access to default Vitest environments through vitest/environments entry:

import { builtinEnvironments, populateGlobal } from 'vitest/environments'

console.log(builtinEnvironments) // { jsdom, happy-dom, node, edge-runtime }

Vitest also provides populateGlobal utility function, which can be used to move properties from object into the global namespace:

interface PopulateOptions {
  // should non-class functions be bind to the global namespace
  bindFunctions?: boolean
}

interface PopulateResult {
  // a list of all keys that were copied, even if value doesn't exist on original object
  keys: Set<string>
  // a map of original object that might have been overriden with keys
  // you can return these values inside `teardown` function
  originals: Map<string | symbol, any>
}

export function populateGlobal(global: any, original: any, options: PopulateOptions): PopulateResult