Add ability to define export conditions per modules

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Features
 
+- `[jest-runtime][jest-environment][jest-environment-jsdom-abstract][jest-environment-node]` Allow more granular custom export conditions in test environment options; conditions can be defined both globally and for a set of modules (TBA)
 - `[babel-jest]` Add option `excludeJestPreset` to allow opting out of `babel-preset-jest` ([#15164](https://github.com/jestjs/jest/pull/15164))
 - `[jest-circus, jest-cli, jest-config]` Add `waitNextEventLoopTurnForUnhandledRejectionEvents` flag to minimise performance impact of correct detection of unhandled promise rejections introduced in [#14315](https://github.com/jestjs/jest/pull/14315) ([#14681](https://github.com/jestjs/jest/pull/14681))
 - `[jest-circus]` Add a `waitBeforeRetry` option to `jest.retryTimes` ([#14738](https://github.com/jestjs/jest/pull/14738))

docs/Configuration.md

@@ -2023,6 +2023,39 @@ const config: Config = {
 export default config;
 ```
 
+In case you need get specific `exports` for a library or set of libraries, you can define it this way:
+
+```js tab
+/** @type {import('jest').Config} */
+const config = {
+  testEnvironment: 'jsdom',
+  testEnvironmentOptions: {
+    customExportConditions: [{
+      modules: ['msw', 'msw/node', '@mswjs/interceptors/*'],
+      conditions: [], // use only basic conditions depending on if it's in CJS/ESM context
+    }],
+  },
+};
+
+module.exports = config;
+```
+
+```ts tab
+import type {Config} from 'jest';
+
+const config: Config = {
+  testEnvironment: 'jsdom',
+  testEnvironmentOptions: {
+    customExportConditions: [{
+      modules: ['msw', 'msw/node', '@mswjs/interceptors/*'],
+      conditions: [], // use only basic conditions depending on if it's in CJS/ESM context
+    }],
+  },
+};
+
+export default config;
+```
+
 These options can also be passed in a docblock, similar to `testEnvironment`. The string with options must be parseable by `JSON.parse`:
 
 ```js

packages/jest-environment-jsdom-abstract/src/index.ts

@@ -7,10 +7,12 @@
 
 import type {Context} from 'vm';
 import type * as jsdom from 'jsdom';
-import type {
-  EnvironmentContext,
-  JestEnvironment,
-  JestEnvironmentConfig,
+import {
+  type EnvironmentContext,
+  type JestEnvironment,
+  type JestEnvironmentConfig,
+  type JestExportConditionsPerModules,
+  isExportConditions,
 } from '@jest/environment';
 import {LegacyFakeTimers, ModernFakeTimers} from '@jest/fake-timers';
 import type {Global} from '@jest/types';
@@ -26,10 +28,6 @@ type Win = Window &
     };
   };
 
-function isString(value: unknown): value is string {
-  return typeof value === 'string';
-}
-
 export default abstract class BaseJSDOMEnvironment
   implements JestEnvironment<number>
 {
@@ -40,7 +38,9 @@ export default abstract class BaseJSDOMEnvironment
   private errorEventListener: ((event: Event & {error: Error}) => void) | null;
   moduleMocker: ModuleMocker | null;
   customExportConditions = ['browser'];
-  private readonly _configuredExportConditions?: Array<string>;
+  private readonly _configuredExportConditions?: Array<
+    string | JestExportConditionsPerModules
+  >;
 
   protected constructor(
     config: JestEnvironmentConfig,
@@ -126,12 +126,12 @@ export default abstract class BaseJSDOMEnvironment
       const {customExportConditions} = projectConfig.testEnvironmentOptions;
       if (
         Array.isArray(customExportConditions) &&
-        customExportConditions.every(isString)
+        customExportConditions.every(isExportConditions)
       ) {
         this._configuredExportConditions = customExportConditions;
       } else {
         throw new Error(
-          'Custom export conditions specified but they are not an array of strings',
+          'Custom export conditions specified but they are not an array of proper shape',
         );
       }
     }
@@ -178,7 +178,7 @@ export default abstract class BaseJSDOMEnvironment
     this.fakeTimersModern = null;
   }
 
-  exportConditions(): Array<string> {
+  exportConditions(): Array<string | JestExportConditionsPerModules> {
     return this._configuredExportConditions ?? this.customExportConditions;
   }
 

packages/jest-environment-node/src/index.ts

@@ -6,10 +6,12 @@
  */
 
 import {type Context, createContext, runInContext} from 'vm';
-import type {
-  EnvironmentContext,
-  JestEnvironment,
-  JestEnvironmentConfig,
+import {
+  type EnvironmentContext,
+  type JestEnvironment,
+  type JestEnvironmentConfig,
+  type JestExportConditionsPerModules,
+  isExportConditions,
 } from '@jest/environment';
 import {LegacyFakeTimers, ModernFakeTimers} from '@jest/fake-timers';
 import type {Global} from '@jest/types';
@@ -56,10 +58,6 @@ const nodeGlobals = new Map(
     }),
 );
 
-function isString(value: unknown): value is string {
-  return typeof value === 'string';
-}
-
 const timerIdToRef = (id: number) => ({
   id,
   ref() {
@@ -79,7 +77,9 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
   global: Global.Global;
   moduleMocker: ModuleMocker | null;
   customExportConditions = ['node', 'node-addons'];
-  private readonly _configuredExportConditions?: Array<string>;
+  private readonly _configuredExportConditions?: Array<
+    string | JestExportConditionsPerModules
+  >;
 
   // while `context` is unused, it should always be passed
   constructor(config: JestEnvironmentConfig, _context: EnvironmentContext) {
@@ -168,12 +168,12 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
       const {customExportConditions} = projectConfig.testEnvironmentOptions;
       if (
         Array.isArray(customExportConditions) &&
-        customExportConditions.every(isString)
+        customExportConditions.every(isExportConditions)
       ) {
         this._configuredExportConditions = customExportConditions;
       } else {
         throw new Error(
-          'Custom export conditions specified but they are not an array of strings',
+          'Custom export conditions specified but they are not an array of proper shape',
         );
       }
     }
@@ -211,7 +211,7 @@ export default class NodeEnvironment implements JestEnvironment<Timer> {
     this.fakeTimersModern = null;
   }
 
-  exportConditions(): Array<string> {
+  exportConditions(): Array<string | JestExportConditionsPerModules> {
     return this._configuredExportConditions ?? this.customExportConditions;
   }
 

packages/jest-environment/src/index.ts

@@ -37,6 +37,37 @@ export interface JestEnvironmentConfig {
   globalConfig: Config.GlobalConfig;
 }
 
+export type JestExportConditionsPerModules = {
+  modules: Array<string>;
+  conditions: Array<string>;
+};
+
+export function isSimpleExportConditionsItem(
+  item: string | JestExportConditionsPerModules,
+): item is string {
+  return typeof item === 'string';
+}
+
+export function isExportConditionsItemPerModules(
+  item: string | JestExportConditionsPerModules,
+): item is JestExportConditionsPerModules {
+  return typeof item !== 'string';
+}
+
+export function isExportConditions(
+  item: unknown,
+): item is string | JestExportConditionsPerModules {
+  return (
+    typeof item === 'string' ||
+    (typeof item === 'object' &&
+      item !== null &&
+      'modules' in item &&
+      'conditions' in item &&
+      Array.isArray((item as JestExportConditionsPerModules).modules) &&
+      Array.isArray((item as JestExportConditionsPerModules).conditions))
+  );
+}
+
 export declare class JestEnvironment<Timer = unknown> {
   constructor(config: JestEnvironmentConfig, context: EnvironmentContext);
   global: Global.Global;
@@ -47,7 +78,7 @@ export declare class JestEnvironment<Timer = unknown> {
   setup(): Promise<void>;
   teardown(): Promise<void>;
   handleTestEvent?: Circus.EventHandler;
-  exportConditions?: () => Array<string>;
+  exportConditions?: () => Array<string | JestExportConditionsPerModules>;
 }
 
 export type Module = NodeModule;