Fix TextEncoder.encode not referencing same global Uint8Array constru…

…ctor (#9261)

CHANGELOG.md

@@ -52,7 +52,9 @@
 - `[jest-core]` Limit number of workers when creating haste maps in projects ([#9259](https://github.com/facebook/jest/pull/9259))
 - `[jest-diff]` Do not inverse format if line consists of one change ([#8903](https://github.com/facebook/jest/pull/8903))
 - `[jest-diff]` Rename some new options and change their default values ([#9077](https://github.com/facebook/jest/pull/9077))
+- `[jest-environment-node]` Fix `TextEncoder.encode` not referencing same global `Uint8Array` constructor ([#9261](https://github.com/facebook/jest/pull/9261))
 - `[jest-fake-timers]` `getTimerCount` will not include cancelled immediates ([#8764](https://github.com/facebook/jest/pull/8764))
+- `[jest-jasmine2, jest-circus]` Improve error message format for Node's assert.fail ([#9262](https://github.com/facebook/jest/pull/9262))
 - `[jest-leak-detector]` [**BREAKING**] Use `weak-napi` instead of `weak` package ([#8686](https://github.com/facebook/jest/pull/8686))
 - `[jest-mock]` Fix for mockReturnValue overriding mockImplementationOnce ([#8398](https://github.com/facebook/jest/pull/8398))
 - `[jest-reporters]` Make node-notifier an optional dependency ([#8918](https://github.com/facebook/jest/pull/8918))
@@ -69,7 +71,6 @@
 - `[jest-utils]` Allow querying process.domain ([#9136](https://github.com/facebook/jest/pull/9136))
 - `[pretty-format]` Correctly detect memoized elements ([#9196](https://github.com/facebook/jest/pull/9196))
 - `[jest-fake-timers]` Support `util.promisify` on `setTimeout` ([#9180](https://github.com/facebook/jest/pull/9180))
-- `[jest-jasmine2, jest-circus]` Improve error message format for Node's assert.fail ([#9262](https://github.com/facebook/jest/pull/9262))
 
 ### Chore & Maintenance
 

packages/expect/src/__tests__/__snapshots__/matchers.test.js.snap

@@ -2067,6 +2067,20 @@ exports[`.toEqual() {pass: false} expect([1]).toEqual([2]) 1`] = `
 <d>  ]</>
 `;
 
+exports[`.toEqual() {pass: false} expect([97, 98, 99]).toEqual([97, 98, 100]) 1`] = `
+<d>expect(</><r>received</><d>).</>toEqual<d>(</><g>expected</><d>) // deep equality</>
+
+<g>- Expected  - 1</>
+<r>+ Received  + 1</>
+
+<d>  Uint8Array [</>
+<d>    97,</>
+<d>    98,</>
+<g>-   100,</>
+<r>+   99,</>
+<d>  ]</>
+`;
+
 exports[`.toEqual() {pass: false} expect({"0": "a", "1": "b", "2": "c"}).toEqual("abc") 1`] = `
 <d>expect(</><r>received</><d>).</>toEqual<d>(</><g>expected</><d>) // deep equality</>
 
@@ -2558,6 +2572,13 @@ Expected: not <g>[1]</>
 
 `;
 
+exports[`.toEqual() {pass: true} expect([97, 98, 99]).not.toEqual([97, 98, 99]) 1`] = `
+<d>expect(</><r>received</><d>).</>not<d>.</>toEqual<d>(</><g>expected</><d>) // deep equality</>
+
+Expected: not <g>[97, 98, 99]</>
+
+`;
+
 exports[`.toEqual() {pass: true} expect([Function anonymous]).not.toEqual(Any<Function>) 1`] = `
 <d>expect(</><r>received</><d>).</>not<d>.</>toEqual<d>(</><g>expected</><d>) // deep equality</>
 

packages/expect/src/__tests__/matchers.test.js

@@ -488,6 +488,7 @@ describe('.toEqual()', () => {
       Immutable.Map({1: Immutable.Map({2: {a: 99}})}),
       Immutable.Map({1: Immutable.Map({2: {a: 11}})}),
     ],
+    [new Uint8Array([97, 98, 99]), new Uint8Array([97, 98, 100])],
     [{a: 1, b: 2}, jestExpect.objectContaining({a: 2})],
     [false, jestExpect.objectContaining({a: 2})],
     [[1, 3], jestExpect.arrayContaining([1, 2])],
@@ -689,6 +690,7 @@ describe('.toEqual()', () => {
       Immutable.Map({1: Immutable.Map({2: {a: 99}})}),
       Immutable.Map({1: Immutable.Map({2: {a: 99}})}),
     ],
+    [new Uint8Array([97, 98, 99]), new Uint8Array([97, 98, 99])],
     [{a: 1, b: 2}, jestExpect.objectContaining({a: 1})],
     [[1, 2, 3], jestExpect.arrayContaining([2, 3])],
     ['abcd', jestExpect.stringContaining('bc')],

packages/jest-environment-node/src/__tests__/node_environment.test.ts

@@ -8,6 +8,8 @@
 import NodeEnvironment = require('../');
 import {makeProjectConfig} from '../../../../TestUtils';
 
+const isTextEncoderDefined = typeof TextEncoder === 'function';
+
 describe('NodeEnvironment', () => {
   it('uses a copy of the process object', () => {
     const env1 = new NodeEnvironment(makeProjectConfig());
@@ -49,4 +51,10 @@ describe('NodeEnvironment', () => {
 
     expect(env.fakeTimersLolex).toBeDefined();
   });
+
+  if (isTextEncoderDefined) {
+    test('TextEncoder references the same global Uint8Array constructor', () => {
+      expect(new TextEncoder().encode('abc')).toBeInstanceOf(Uint8Array);
+    });
+  }
 });

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

@@ -46,6 +46,11 @@ class NodeEnvironment implements JestEnvironment {
     global.setInterval = setInterval;
     global.setTimeout = setTimeout;
     global.ArrayBuffer = ArrayBuffer;
+    // TextEncoder (global or via 'util') references a Uint8Array constructor
+    // different than the global one used by users in tests. This makes sure the
+    // same constructor is referenced by both.
+    global.Uint8Array = Uint8Array;
+
     // URL and URLSearchParams are global in Node >= 10
     if (typeof URL !== 'undefined' && typeof URLSearchParams !== 'undefined') {
       global.URL = URL;