feat(vitest): expose jsdom global if jsdom environment is enabled (#5155)

Author: sheremet-va

docs/config/index.md

@@ -511,6 +511,10 @@ export default <Environment>{
 
 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](/guide/environment).
 
+::: tip
+Since Vitest 1.3.0 jsdom environment exposes `jsdom` global variable equal to the current [JSDOM](https://github.com/jsdom/jsdom) instance.
+:::
+
 ### environmentOptions
 
 - **Type:** `Record<'jsdom' | string, unknown>`

packages/vitest/src/integrations/env/jsdom.ts

@@ -67,6 +67,7 @@ export default <Environment>({
 
     // TODO: browser doesn't expose Buffer, but a lot of dependencies use it
     dom.window.Buffer = Buffer
+    dom.window.jsdom = dom
 
     // inject web globals if they missing in JSDOM but otherwise available in Nodejs
     // https://nodejs.org/dist/latest/docs/api/globals.html
@@ -141,10 +142,13 @@ export default <Environment>({
 
     const clearWindowErrors = catchWindowErrors(global)
 
+    global.jsdom = dom
+
     return {
       teardown(global) {
         clearWindowErrors()
         dom.window.close()
+        delete global.jsdom
         keys.forEach(key => delete global[key])
         originals.forEach((v, k) => global[k] = v)
       },