refactor: JsWithBabelPreset not compat with original transform type

e2e/presets/__tests__/presets.spec.ts

@@ -1,6 +1,8 @@
 import { JS_EXT_TO_TREAT_AS_ESM, TS_EXT_TO_TREAT_AS_ESM } from 'ts-jest'
 import presets from 'ts-jest/presets'
 
+import extendedJestConfig from '../extended-jest-config'
+
 const defaultPreset = require('ts-jest/jest-preset')
 
 test('presets', () => {
@@ -75,3 +77,7 @@ test('presets', () => {
     },
   })
 })
+
+test('should allow extending jest config without type issues when using create preset util functions', () => {
+  expect(extendedJestConfig).toBeTruthy()
+})

e2e/presets/extended-jest-config.ts

@@ -0,0 +1,48 @@
+import {
+  createDefaultPreset,
+  createDefaultEsmPreset,
+  createJsWithTsPreset,
+  createJsWithTsEsmPreset,
+  createJsWithBabelPreset,
+  createJsWithBabelEsmPreset,
+  type JestConfigWithTsJest,
+} from 'ts-jest'
+
+const defaultPreset: JestConfigWithTsJest = {
+  ...createDefaultPreset(),
+  testEnvironment: 'jsdom',
+}
+
+const defaultEsmPreset: JestConfigWithTsJest = {
+  ...createDefaultEsmPreset(),
+  testEnvironment: 'jsdom',
+}
+
+const jsWithTsPreset: JestConfigWithTsJest = {
+  ...createJsWithTsPreset(),
+  testEnvironment: 'jsdom',
+}
+
+const jsWithTsEsmPreset: JestConfigWithTsJest = {
+  ...createJsWithTsEsmPreset(),
+  testEnvironment: 'jsdom',
+}
+
+const jsWithBabelPreset: JestConfigWithTsJest = {
+  ...createJsWithBabelPreset(),
+  testEnvironment: 'jsdom',
+}
+
+const jsWithBabelEsmPreset: JestConfigWithTsJest = {
+  ...createJsWithBabelEsmPreset(),
+  testEnvironment: 'jsdom',
+}
+
+export default {
+  defaultPreset,
+  defaultEsmPreset,
+  jsWithTsPreset,
+  jsWithTsEsmPreset,
+  jsWithBabelPreset,
+  jsWithBabelEsmPreset,
+}

src/cli/__snapshots__/cli.spec.ts.snap

@@ -25,7 +25,7 @@ exports[`config init should create a jest config file with cli options for confi
 module.exports = {
   testEnvironment: "jsdom",
   transform: {
-    "^.+.jsx?$": ["babel-jest",{}],
+    "^.+.jsx?$": "babel-jest",
   },
 };"
 `;
@@ -35,7 +35,7 @@ exports[`config init should create a jest config file with cli options for confi
 export default {
   testEnvironment: "jsdom",
   transform: {
-    "^.+.jsx?$": ["babel-jest",{}],
+    "^.+.jsx?$": "babel-jest",
   },
 };"
 `;
@@ -81,15 +81,11 @@ exports[`config init should update package.json for config type js-with-babel-fu
   "version": "0.0.0-mock.0",
   "jest": {
     "transform": {
-      "^.+.jsx?$": [
-        "babel-jest",
-        {}
-      ],
+      "^.+.jsx?$": "babel-jest",
       "^.+.tsx?$": [
         "ts-jest",
         {
-          "tsconfig": "tsconfig.test.json",
-          "babelConfig": true
+          "tsconfig": "tsconfig.test.json"
         }
       ]
     }

src/presets/__snapshots__/create-jest-preset.spec.ts.snap

@@ -30,16 +30,13 @@ exports[`create-jest-preset CJS presets createJsWithTsPreset should return prese
 exports[`create-jest-preset CJS presets createWithBabelPreset should return preset config 1`] = `
 {
   "transform": {
-    "^.+.jsx?$": [
-      "babel-jest",
-      {
-        "babelrc": true,
-      },
-    ],
+    "^.+.jsx?$": "babel-jest",
     "^.+.tsx?$": [
       "ts-jest",
       {
-        "babelConfig": true,
+        "babelConfig": {
+          "babelrc": true,
+        },
         "tsconfig": "tsconfig.spec.json",
       },
     ],
@@ -97,12 +94,7 @@ exports[`create-jest-preset ESM presets createWithBabelEsmPreset should return p
     ".mts",
   ],
   "transform": {
-    "^.+\\.m?jsx?$": [
-      "babel-jest",
-      {
-        "babelrc": true,
-      },
-    ],
+    "^.+\\.m?jsx?$": "babel-jest",
     "^.+\\.m?tsx?$": [
       "ts-jest",
       {

src/presets/create-jest-preset.ts

@@ -11,7 +11,6 @@ import {
   ESM_JS_TRANSFORM_PATTERN,
 } from '../constants'
 import type {
-  BabelConfig,
   DefaultPreset,
   JsWithBabelPreset,
   JsWithTsPreset,
@@ -78,18 +77,10 @@ export function createJsWithBabelPreset(
 ): JsWithBabelPreset {
   logger.debug('creating JS with Babel CJS Jest preset')
 
-  const babelConfig = tsJestTransformOptions.babelConfig
-
   return {
     transform: {
-      [JS_TRANSFORM_PATTERN]: ['babel-jest', typeof babelConfig === 'object' ? babelConfig : {}],
-      [TS_TRANSFORM_PATTERN]: [
-        'ts-jest',
-        {
-          ...tsJestTransformOptions,
-          babelConfig: true,
-        },
-      ],
+      [JS_TRANSFORM_PATTERN]: 'babel-jest',
+      [TS_TRANSFORM_PATTERN]: ['ts-jest', tsJestTransformOptions],
     },
   }
 }
@@ -141,24 +132,21 @@ export function createJsWithTsEsmPreset(tsJestTransformOptions: Omit<TsJestTrans
 export function createJsWithBabelEsmPreset(tsJestTransformOptions: Omit<TsJestTransformerOptions, 'useESM'> = {}): {
   extensionsToTreatAsEsm: string[]
   transform: {
-    [ESM_JS_TRANSFORM_PATTERN]: ['babel-jest', babelConfig: BabelConfig]
+    [ESM_JS_TRANSFORM_PATTERN]: 'babel-jest'
     [ESM_TS_TRANSFORM_PATTERN]: ['ts-jest', { useESM: true } & typeof tsJestTransformOptions]
   }
 } {
   logger.debug('creating JS with Babel ESM Jest preset')
 
-  const babelConfig = tsJestTransformOptions.babelConfig
-
   return {
     extensionsToTreatAsEsm: [...JS_EXT_TO_TREAT_AS_ESM, ...TS_EXT_TO_TREAT_AS_ESM],
     transform: {
-      [ESM_JS_TRANSFORM_PATTERN]: ['babel-jest', typeof babelConfig === 'object' ? babelConfig : {}],
+      [ESM_JS_TRANSFORM_PATTERN]: 'babel-jest',
       [ESM_TS_TRANSFORM_PATTERN]: [
         'ts-jest',
         {
           ...tsJestTransformOptions,
           useESM: true,
-          babelConfig,
         },
       ],
     },

src/types.ts

@@ -250,7 +250,7 @@ export type JsWithTsPreset = {
 }
 export type JsWithBabelPreset = {
   transform: {
-    [JS_TRANSFORM_PATTERN]: ['babel-jest', babelConfig: BabelConfig]
+    [JS_TRANSFORM_PATTERN]: 'babel-jest'
     [TS_TRANSFORM_PATTERN]: ['ts-jest', Omit<TsJestTransformerOptions, 'useESM'>]
   }
 }