fix: improved performance (only node@12 and above) (#344)

Author: evilebottnawi

src/index.js

@@ -126,7 +126,10 @@ class TerserPlugin {
 
       concurrency = numWorkers;
 
-      worker = new Worker(require.resolve('./minify'), { numWorkers });
+      worker = new Worker(require.resolve('./minify'), {
+        numWorkers,
+        enableWorkerThreads: true,
+      });
 
       // https://github.com/facebook/jest/issues/8872#issuecomment-524822081
       const workerStdout = worker.getStdout();

test/parallel-option.test.js

@@ -27,6 +27,11 @@ jest.mock('os', () => {
 let workerTransform;
 let workerEnd;
 
+const ENABLE_WORKER_THREADS =
+  typeof process.env.ENABLE_WORKER_THREADS !== 'undefined'
+    ? process.env.ENABLE_WORKER_THREADS === 'true'
+    : true;
+
 jest.mock('jest-worker', () => {
   return jest.fn().mockImplementation((workerPath) => {
     return {
@@ -67,6 +72,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: os.cpus().length - 1,
     });
     expect(workerTransform).toHaveBeenCalledTimes(
@@ -98,6 +104,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: Math.min(4, os.cpus().length - 1),
     });
     expect(workerTransform).toHaveBeenCalledTimes(
@@ -117,6 +124,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: 2,
     });
     expect(workerTransform).toHaveBeenCalledTimes(
@@ -140,6 +148,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: Math.min(1, os.cpus().length - 1),
     });
     expect(workerTransform).toHaveBeenCalledTimes(
@@ -167,6 +176,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: Math.min(Object.keys(entries).length, os.cpus().length - 1),
     });
     expect(workerTransform).toHaveBeenCalledTimes(
@@ -194,6 +204,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: Math.min(Object.keys(entries).length, os.cpus().length - 1),
     });
     expect(workerTransform).toHaveBeenCalledTimes(
@@ -232,6 +243,7 @@ describe('parallel option', () => {
 
     expect(Worker).toHaveBeenCalledTimes(1);
     expect(Worker).toHaveBeenLastCalledWith(workerPath, {
+      enableWorkerThreads: ENABLE_WORKER_THREADS,
       numWorkers: Math.min(Object.keys(entries).length, os.cpus().length - 1),
     });
     expect(workerTransform).toHaveBeenCalledTimes(