extract jest setup refactor from #482

jest.config.ts

@@ -1,28 +1,8 @@
 import type { Config } from '@jest/types';
-import nextJest from 'next/jest';
 
-const createJestConfig = nextJest({
-  // Provide the path to your Next.js app to load next.config.js and .env files in your test environment
-  dir: '<rootDir>/packages/toolpad-app',
-});
+const config: Config.InitialOptions = {
+  projects: ['<rootDir>/packages/toolpad-app/jest.config.js'],
+  setupFilesAfterEnv: ['<rootDir>/test/utils/jest-setup.ts'],
+};
 
-export default async function createConfig() {
-  const nextJestConfig: Config.InitialOptions = await createJestConfig({
-    testEnvironment: 'jest-environment-jsdom',
-  })();
-
-  // Workaround, see https://github.com/vercel/next.js/issues/35634#issuecomment-1115250297
-  nextJestConfig.transformIgnorePatterns[0] = '/node_modules/(?!lodash-es)/';
-
-  const config: Config.InitialOptions = {
-    projects: [
-      {
-        testMatch: ['<rootDir>/packages/toolpad-app/**/*.spec.*'],
-        ...nextJestConfig,
-      },
-    ],
-    setupFilesAfterEnv: ['<rootDir>/test/utils/jest-setup.ts'],
-  };
-
-  return config;
-}
+export default config;

packages/toolpad-app/jest.config.js

@@ -0,0 +1,14 @@
+const nextJest = require('next/jest');
+
+const createJestConfig = nextJest();
+
+async function jestConfig() {
+  const nextJestConfig = await createJestConfig({
+    testEnvironment: 'jest-environment-jsdom',
+  })();
+  // Workaround, see https://github.com/vercel/next.js/issues/35634#issuecomment-1115250297
+  nextJestConfig.transformIgnorePatterns[0] = '/node_modules/(?!lodash-es)/';
+  return nextJestConfig;
+}
+
+module.exports = jestConfig;