feat: support conditions from test environments

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### Features
 
 - `[jest-resolver, jest-runtime]` Pass `conditions` to custom resolvers to enable them to implement support for package.json `exports` field ([#11859](https://github.com/facebook/jest/pull/11859))
+- `[jest-runtime]` Allow custom envs to specify `exportConditions` which is passed together with Jest's own conditions to custom resolvers ([#11863](https://github.com/facebook/jest/pull/11863))
 
 ### Fixes
 

docs/Configuration.md

@@ -851,7 +851,7 @@ module.exports = (request, options) => {
 };
 ```
 
-While Jest does not support [package `exports`](https://nodejs.org/api/packages.html#packages_package_entry_points) (beyond `main`), Jest will provide `conditions` as an option when calling custom resolvers, which can be used to implement support for `exports` in userland. Jest will pass `['import', 'default']` when running a test in ESM mode, and `['require', 'default']` when running with CJS.
+While Jest does not support [package `exports`](https://nodejs.org/api/packages.html#packages_package_entry_points) (beyond `main`), Jest will provide `conditions` as an option when calling custom resolvers, which can be used to implement support for `exports` in userland. Jest will pass `['import', 'default']` when running a test in ESM mode, and `['require', 'default']` when running with CJS. Additionally, custom test environments can specify an `exportConditions` method which returns an array of conditions that will be passed along with Jest's defaults.
 
 ### `restoreMocks` \[boolean]
 

e2e/resolve-conditions/__tests__/browser.test.mjs

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @jest-environment <rootDir>/browser-env.js
+ */
+
+import {fn} from '../fake-dual-dep';
+
+test('returns correct message', () => {
+  expect(fn()).toEqual('hello from browser');
+});

e2e/resolve-conditions/__tests__/node.test.mjs

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @jest-environment <rootDir>/node-env.js
+ */
+
+import {fn} from '../fake-dual-dep';
+
+test('returns correct message', () => {
+  expect(fn()).toEqual('hello from node');
+});

e2e/resolve-conditions/browser-env.js

@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+const BrowserEnv = require('jest-environment-jsdom');
+
+module.exports = class BrowserEnvWithConditions extends BrowserEnv {
+  exportConditions() {
+    return ['browser'];
+  }
+};

e2e/resolve-conditions/fake-dual-dep/browser.mjs

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+export function fn() {
+  return 'hello from browser';
+}

e2e/resolve-conditions/fake-dual-dep/node.mjs

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+export function fn() {
+  return 'hello from node';
+}

e2e/resolve-conditions/fake-dual-dep/package.json

@@ -0,0 +1,10 @@
+{
+  "name": "fake-dual-dep",
+  "version": "1.0.0",
+  "exports": {
+    ".": {
+      "node": "./node.mjs",
+      "browser": "./browser.mjs"
+    }
+  }
+}

e2e/resolve-conditions/node-env.js

@@ -0,0 +1,16 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+const NodeEnv = require('jest-environment-node');
+
+module.exports = class NodeEnvWithConditions extends NodeEnv {
+  exportConditions() {
+    return ['node'];
+  }
+};

e2e/resolve-conditions/resolver.js

@@ -25,9 +25,11 @@ function createPathFilter(conditions) {
 
     return (
       resolveExports(pkg, path, {
+        // `resolve.exports adds `node` unless `browser` is `false`, so let's add this ugly thing
+        browser: conditions.includes('browser'),
         conditions,
         // `resolve.exports adds `import` unless `require` is `false`, so let's add this ugly thing
-        require: !conditions.includes('import'),
+        require: conditions.includes('require'),
       }) || relativePath
     );
   };

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

@@ -18,7 +18,7 @@ type Timer = {
   unref: () => Timer;
 };
 
-class NodeEnvironment implements JestEnvironment {
+class NodeEnvironment implements JestEnvironment<Timer> {
   context: Context | null;
   fakeTimers: LegacyFakeTimers<Timer> | null;
   fakeTimersModern: ModernFakeTimers | null;

packages/jest-environment/src/index.ts

@@ -42,6 +42,7 @@ export declare class JestEnvironment<Timer = unknown> {
   setup(): Promise<void>;
   teardown(): Promise<void>;
   handleTestEvent?: Circus.EventHandler;
+  exportConditions?: () => Array<string>;
 }
 
 export type Module = NodeModule;

packages/jest-runtime/src/index.ts

@@ -173,10 +173,6 @@ const supportsNodeColonModulePrefixInImport = (() => {
   return stdout === 'true';
 })();
 
-// consider `node` & `browser` condition as well - maybe switching on `global.window` in the test env?
-const esmConditions = ['import', 'default'];
-const cjsConditions = ['require', 'default'];
-
 export default class Runtime {
   private readonly _cacheFS: Map<string, string>;
   private readonly _config: Config.ProjectConfig;
@@ -228,6 +224,8 @@ export default class Runtime {
   private _moduleImplementation?: typeof nativeModule.Module;
   private readonly jestObjectCaches: Map<string, Jest>;
   private jestGlobals?: JestGlobals;
+  private readonly esmConditions: Array<string>;
+  private readonly cjsConditions: Array<string>;
 
   constructor(
     config: Config.ProjectConfig,
@@ -292,6 +290,15 @@ export default class Runtime {
       unmockRegExpCache.set(config, this._unmockList);
     }
 
+    const envExportConditions = this._environment.exportConditions?.() ?? [];
+
+    this.esmConditions = Array.from(
+      new Set(['import', 'default', ...envExportConditions]),
+    );
+    this.cjsConditions = Array.from(
+      new Set(['require', 'default', ...envExportConditions]),
+    );
+
     if (config.automock) {
       config.setupFiles.forEach(filePath => {
         if (filePath.includes(NODE_MODULES)) {
@@ -302,8 +309,8 @@ export default class Runtime {
             // shouldn't really matter, but in theory this will make sure the caching is correct
             {
               conditions: this.unstable_shouldLoadAsEsm(filePath)
-                ? esmConditions
-                : cjsConditions,
+                ? this.esmConditions
+                : this.cjsConditions,
             },
           );
           this._transitiveShouldMock.set(moduleID, false);
@@ -547,14 +554,14 @@ export default class Runtime {
         referencingIdentifier,
         path,
         this._explicitShouldMockModule,
-        {conditions: esmConditions},
+        {conditions: this.esmConditions},
       )
     ) {
       return this.importMock(referencingIdentifier, path, context);
     }
 
     const resolved = this._resolveModule(referencingIdentifier, path, {
-      conditions: esmConditions,
+      conditions: this.esmConditions,
     });
 
     if (
@@ -604,7 +611,7 @@ export default class Runtime {
     const [path, query] = (moduleName ?? '').split('?');
 
     const modulePath = this._resolveModule(from, path, {
-      conditions: esmConditions,
+      conditions: this.esmConditions,
     });
 
     const module = await this.loadEsmModule(modulePath, query);
@@ -655,7 +662,7 @@ export default class Runtime {
       this._virtualModuleMocks,
       from,
       moduleName,
-      {conditions: esmConditions},
+      {conditions: this.esmConditions},
     );
 
     if (this._moduleMockRegistry.has(moduleID)) {
@@ -703,7 +710,7 @@ export default class Runtime {
 
     reexports.forEach(reexport => {
       const resolved = this._resolveModule(modulePath, reexport, {
-        conditions: esmConditions,
+        conditions: this.esmConditions,
       });
 
       const exports = this.getExportsOfCjs(resolved);
@@ -727,7 +734,7 @@ export default class Runtime {
       this._virtualMocks,
       from,
       moduleName,
-      isInternal ? undefined : {conditions: cjsConditions},
+      isInternal ? undefined : {conditions: this.cjsConditions},
     );
     let modulePath: string | undefined;
 
@@ -758,7 +765,7 @@ export default class Runtime {
       modulePath = this._resolveModule(
         from,
         moduleName,
-        isInternal ? undefined : {conditions: cjsConditions},
+        isInternal ? undefined : {conditions: this.cjsConditions},
       );
     }
 
@@ -851,7 +858,7 @@ export default class Runtime {
       this._virtualMocks,
       from,
       moduleName,
-      {conditions: cjsConditions},
+      {conditions: this.cjsConditions},
     );
 
     const mockRegistry = this._isolatedMockRegistry || this._mockRegistry;
@@ -871,7 +878,7 @@ export default class Runtime {
 
     let modulePath =
       this._resolver.getMockModule(from, moduleName) ||
-      this._resolveModule(from, moduleName, {conditions: cjsConditions});
+      this._resolveModule(from, moduleName, {conditions: this.cjsConditions});
 
     let isManualMock =
       manualMockOrStub &&
@@ -977,7 +984,7 @@ export default class Runtime {
     try {
       if (
         this._shouldMock(from, moduleName, this._explicitShouldMock, {
-          conditions: cjsConditions,
+          conditions: this.cjsConditions,
         })
       ) {
         return this.requireMock<T>(from, moduleName);
@@ -1122,7 +1129,7 @@ export default class Runtime {
       this._virtualMocks,
       from,
       moduleName,
-      {conditions: cjsConditions},
+      {conditions: this.cjsConditions},
     );
     this._explicitShouldMock.set(moduleID, true);
     this._mockFactories.set(moduleID, mockFactory);
@@ -1143,7 +1150,7 @@ export default class Runtime {
       this._virtualModuleMocks,
       from,
       moduleName,
-      {conditions: esmConditions},
+      {conditions: this.esmConditions},
     );
     this._explicitShouldMockModule.set(moduleID, true);
     this._moduleMockFactories.set(moduleID, mockFactory);
@@ -1220,7 +1227,7 @@ export default class Runtime {
           absolutePath,
           moduleName,
           // required to also resolve files without leading './' directly in the path
-          {conditions: cjsConditions, paths: [absolutePath]},
+          {conditions: this.cjsConditions, paths: [absolutePath]},
         );
         if (module) {
           return module;
@@ -1234,7 +1241,9 @@ export default class Runtime {
       );
     }
     try {
-      return this._resolveModule(from, moduleName, {conditions: cjsConditions});
+      return this._resolveModule(from, moduleName, {
+        conditions: this.cjsConditions,
+      });
     } catch (err) {
       const module = this._resolver.getMockModule(from, moduleName);
 
@@ -1589,7 +1598,7 @@ export default class Runtime {
   private _generateMock(from: Config.Path, moduleName: string) {
     const modulePath =
       this._resolver.resolveStubModuleName(from, moduleName) ||
-      this._resolveModule(from, moduleName, {conditions: cjsConditions});
+      this._resolveModule(from, moduleName, {conditions: this.cjsConditions});
     if (!this._mockMetaDataCache.has(modulePath)) {
       // This allows us to handle circular dependencies while generating an
       // automock
@@ -1772,7 +1781,7 @@ export default class Runtime {
         this._virtualMocks,
         from,
         moduleName,
-        {conditions: cjsConditions},
+        {conditions: this.cjsConditions},
       );
       this._explicitShouldMock.set(moduleID, false);
       return jestObject;
@@ -1782,7 +1791,7 @@ export default class Runtime {
         this._virtualMocks,
         from,
         moduleName,
-        {conditions: cjsConditions},
+        {conditions: this.cjsConditions},
       );
       this._explicitShouldMock.set(moduleID, false);
       this._transitiveShouldMock.set(moduleID, false);
@@ -1797,7 +1806,7 @@ export default class Runtime {
         this._virtualMocks,
         from,
         moduleName,
-        {conditions: cjsConditions},
+        {conditions: this.cjsConditions},
       );
       this._explicitShouldMock.set(moduleID, true);
       return jestObject;