fix: properly inject extraGlobals into the environment

e2e/__tests__/extraGlobals.test.ts

@@ -0,0 +1,34 @@
+/**
+ * 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.
+ */
+
+import * as path from 'path';
+import {tmpdir} from 'os';
+import {json as runJest} from '../runJest';
+import {cleanup, createEmptyPackage, writeFiles} from '../Utils';
+
+const DIR = path.resolve(tmpdir(), 'extra-globals');
+
+beforeEach(() => {
+  cleanup(DIR);
+  createEmptyPackage(DIR, {jest: {extraGlobals: ['Math']}});
+});
+
+afterAll(() => cleanup(DIR));
+
+test('works with injected globals', () => {
+  writeFiles(DIR, {
+    'test.js': `
+       test('Math works when injected', () => {
+         expect(Math.floor(1.5)).toBe(1);
+       });
+  `,
+  });
+
+  const {exitCode} = runJest(DIR);
+
+  expect(exitCode).toBe(0);
+});

packages/jest-runtime/src/index.ts

@@ -1097,7 +1097,7 @@ class Runtime {
 
     const lastArgs: [Jest | undefined, ...Array<any>] = [
       this._config.injectGlobals ? jestObject : undefined, // jest object
-      this._config.extraGlobals.map<unknown>(globalVariable => {
+      ...this._config.extraGlobals.map<unknown>(globalVariable => {
         if (this._environment.global[globalVariable]) {
           return this._environment.global[globalVariable];
         }