remove enableWorkerThreads

Author: SimenB

packages/jest-worker/README.md

@@ -43,8 +43,6 @@ export function hello(param) {
 
 Node 10 shipped with [worker-threads](https://nodejs.org/api/worker_threads.html), a "threading API" that uses SharedArrayBuffers to communicate between the main process and its child threads. This experimental Node feature can significantly improve the communication time between parent and child processes in `jest-worker`.
 
-Since `worker_threads` are considered experimental in Node, you have to opt-in to this behavior by passing `enableWorkerThreads: true` when instantiating the worker. While the feature was unflagged in Node 11.7.0, you'll need to run the Node process with the `--experimental-worker` flag for Node 10.
-
 ## API
 
 The only exposed method is a constructor (`Worker`) that is initialized by passing the worker path, plus an options object.
@@ -89,10 +87,6 @@ Provide a custom worker pool to be used for spawning child processes. By default
 
 The arguments that will be passed to the `setup` method during initialization.
 
-#### `enableWorkerThreads: boolean` (optional)
-
-`jest-worker` will automatically detect if `worker_threads` are available, but will not use them unless passed `enableWorkerThreads: true`.
-
 ## Worker
 
 The returned `Worker` instance has all the exposed methods, plus some additional ones to interact with the workers itself:

packages/jest-worker/src/WorkerPool.ts

@@ -37,7 +37,7 @@ class WorkerPool extends BaseWorkerPool implements WorkerPoolInterface {
 
   createWorker(workerOptions: WorkerOptions): WorkerInterface {
     let Worker;
-    if (this._options.enableWorkerThreads && canUseWorkerThreads()) {
+    if (canUseWorkerThreads()) {
       Worker = require('./workers/NodeThreadsWorker').default;
     } else {
       Worker = require('./workers/ChildProcessWorker').default;

packages/jest-worker/src/__tests__/WorkerPool.test.js

@@ -77,7 +77,6 @@ describe('WorkerPool', () => {
   it('should create a NodeThreadWorker and send to it', () => {
     jest.mock('worker_threads', () => 'Defined');
     const workerPool = new WorkerPool('/path', {
-      enableWorkerThreads: true,
       forkOptions: {},
       maxRetries: 1,
       numWorkers: 1,
@@ -102,32 +101,4 @@ describe('WorkerPool', () => {
       onEnd,
     );
   });
-
-  it('should avoid NodeThreadWorker if not passed enableWorkerThreads', () => {
-    jest.mock('worker_threads', () => 'Defined');
-    const workerPool = new WorkerPool('/path', {
-      forkOptions: {},
-      maxRetries: 1,
-      numWorkers: 1,
-      workerId: 0,
-      workerPath: '/path',
-    });
-
-    const onStart = () => {};
-    const onEnd = () => {};
-    workerPool.send(0, {foo: 'bar'}, onStart, onEnd);
-
-    expect(ChildProcessWorker).toBeCalledWith({
-      forkOptions: {},
-      maxRetries: 1,
-      workerId: 0,
-      workerPath: '/path',
-    });
-    expect(NodeThreadWorker).not.toBeCalled();
-    expect(workerPool._workers[0].send).toBeCalledWith(
-      {foo: 'bar'},
-      onStart,
-      onEnd,
-    );
-  });
 });

packages/jest-worker/src/__tests__/thread-integration.test.js

@@ -66,7 +66,6 @@ describe('Jest Worker Process Integration', () => {
 
   it('calls a single method from the worker', async () => {
     const farm = new Farm('/tmp/baz.js', {
-      enableWorkerThreads: true,
       exposedMethods: ['foo', 'bar'],
       numWorkers: 4,
     });
@@ -80,7 +79,6 @@ describe('Jest Worker Process Integration', () => {
 
   it('distributes sequential calls across child processes', async () => {
     const farm = new Farm('/tmp/baz.js', {
-      enableWorkerThreads: true,
       exposedMethods: ['foo', 'bar'],
       numWorkers: 4,
     });
@@ -102,7 +100,6 @@ describe('Jest Worker Process Integration', () => {
 
   it('distributes concurrent calls across child processes', async () => {
     const farm = new Farm('/tmp/baz.js', {
-      enableWorkerThreads: true,
       exposedMethods: ['foo', 'bar'],
       numWorkers: 4,
     });
@@ -131,7 +128,6 @@ describe('Jest Worker Process Integration', () => {
   it('sticks parallel calls to children', async () => {
     const farm = new Farm('/tmp/baz.js', {
       computeWorkerKey: () => '1234567890abcdef',
-      enableWorkerThreads: true,
       exposedMethods: ['foo', 'bar'],
       numWorkers: 4,
     });

packages/jest-worker/src/index.ts

@@ -74,7 +74,6 @@ export default class JestWorker {
     this._ending = false;
 
     const workerPoolOptions: WorkerPoolOptions = {
-      enableWorkerThreads: this._options.enableWorkerThreads || false,
       forkOptions: this._options.forkOptions || {},
       maxRetries: this._options.maxRetries || 3,
       numWorkers: this._options.numWorkers || Math.max(cpus().length - 1, 1),

packages/jest-worker/src/types.ts

@@ -71,15 +71,13 @@ export type FarmOptions = {
     workerPath: string,
     options?: WorkerPoolOptions,
   ) => WorkerPoolInterface;
-  enableWorkerThreads?: boolean;
 };
 
 export type WorkerPoolOptions = {
   setupArgs: Array<unknown>;
   forkOptions: ForkOptions;
   maxRetries: number;
   numWorkers: number;
-  enableWorkerThreads: boolean;
 };
 
 export type WorkerOptions = {