feat(posts): add "How to fix Next.js import Jest error"

Post: 2025-08-14-fix-next-import-jest-error.md

Author: remarkablemark

_posts/2025/2025-08-14-fix-next-import-jest-error.md

@@ -0,0 +1,40 @@
+---
+layout: post
+title: How to fix Next.js import Jest error
+date: 2025-08-14 22:14:29
+excerpt: How to fix Next.js import Jest error.
+categories: next jest typescript test
+---
+
+## Problem
+
+If you've updated [Next.js](https://nextjs.org/) and got the Jest test error:
+
+```sh
+npm test
+```
+
+```
+Error: Jest: Failed to parse the TypeScript config file /home/runner/work/nextjs-typescript-template/nextjs-typescript-template/jest.config.ts
+  Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/next/jest' imported from /home/runner/work/nextjs-typescript-template/nextjs-typescript-template/jest.config.ts
+Did you mean to import "next/jest.js"?
+    at readConfigFileAndSetRootDir (/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/jest-config/build/index.js:2269:13)
+    at async readInitialOptions (/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/jest-config/build/index.js:1147:13)
+    at async readConfig (/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/jest-config/build/index.js:918:7)
+    at async readConfigs (/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/jest-config/build/index.js:1168:26)
+    at async runCLI (/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/@jest/core/build/index.js:1393:7)
+    at async Object.run (/home/runner/work/nextjs-typescript-template/nextjs-typescript-template/node_modules/jest-cli/build/index.js:656:9)
+```
+
+## Solution
+
+The fix is that you need to replace `next/jest` with `next/jest.js` if you're using [TypeScript](https://nextjs.org/docs/app/guides/testing/jest#manual-setup):
+
+```diff
+ // jest.config.ts
+ import type { Config } from 'jest'
+-import nextJest from 'next/jest'
++import nextJest from 'next/jest.js'
+```
+
+See [example](https://github.com/remarkablemark/nextjs-typescript-template/commit/8faa647090427fcf7bc5ae4736b97b1fef1f1ab2).