From 9faf14e0b77326bc07a1cb39e6837a83d6aa3e6e Mon Sep 17 00:00:00 2001
From: Tim Neutkens <tim@timneutkens.nl>
Date: Thu, 11 Nov 2021 16:05:32 +0100
Subject: [PATCH] next/jest: Ensure typeof window is not transformed in jsdom
 environment (#31304)

Found that when the target is `jsdom` instead of `node` the "typeof window" transform is incorrect. This was causing an unexpected failure in on of the tests for vercel.com.


## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `yarn lint`
---
 packages/next/build/swc/jest-transformer.js | 13 ++++++++-----
 packages/next/build/swc/options.js          |  3 ++-
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/packages/next/build/swc/jest-transformer.js b/packages/next/build/swc/jest-transformer.js
index b2da3d124889ad2..72dfc686f393530 100644
--- a/packages/next/build/swc/jest-transformer.js
+++ b/packages/next/build/swc/jest-transformer.js
@@ -41,14 +41,19 @@ module.exports = {
         return src
       }
 
+      const jestConfig = getJestConfig(jestOptions)
+
       let swcTransformOpts = getJestSWCOptions({
+        // When target is node it's similar to the server option set in SWC.
+        isServer:
+          jestConfig.testEnvironment && jestConfig.testEnvironment === 'node',
         filename,
         styledComponents: inputOptions.styledComponents,
         paths: inputOptions.paths,
         baseUrl: inputOptions.resolvedBaseUrl,
         esm:
           isSupportEsm &&
-          isEsm(Boolean(inputOptions.isEsmProject), filename, jestOptions),
+          isEsm(Boolean(inputOptions.isEsmProject), filename, jestConfig),
       })
 
       return transformSync(src, { ...swcTransformOpts, filename })
@@ -64,11 +69,9 @@ function getJestConfig(jestConfig) {
       jestConfig
 }
 
-function isEsm(isEsmProject, filename, jestOptions) {
+function isEsm(isEsmProject, filename, jestConfig) {
   return (
     (/\.jsx?$/.test(filename) && isEsmProject) ||
-    getJestConfig(jestOptions).extensionsToTreatAsEsm?.find((ext) =>
-      filename.endsWith(ext)
-    )
+    jestConfig.extensionsToTreatAsEsm?.find((ext) => filename.endsWith(ext))
   )
 }
diff --git a/packages/next/build/swc/options.js b/packages/next/build/swc/options.js
index e3d454f00165119..ea025465366585b 100644
--- a/packages/next/build/swc/options.js
+++ b/packages/next/build/swc/options.js
@@ -60,6 +60,7 @@ function getBaseSWCOptions({
 }
 
 export function getJestSWCOptions({
+  isServer,
   filename,
   esm,
   styledComponents,
@@ -70,7 +71,7 @@ export function getJestSWCOptions({
     filename,
     development: false,
     hasReactRefresh: false,
-    globalWindow: false,
+    globalWindow: !isServer,
     styledComponents,
     paths,
     baseUrl,