fix(terser): don't assume code is running in worker created by the worker pool (#1483)

* fix(terser): don't assume code is running in worker created by the worker pool

* sort imports

Author: dasa

packages/terser/src/constants.ts

@@ -1,2 +1,3 @@
 export const taskInfo = Symbol('taskInfo');
 export const freeWorker = Symbol('freeWorker');
+export const workerPoolWorkerFlag = 'WorkerPoolWorker';

packages/terser/src/worker-pool.ts

@@ -5,7 +5,7 @@ import { EventEmitter } from 'events';
 
 import serializeJavascript from 'serialize-javascript';
 
-import { freeWorker, taskInfo } from './constants';
+import { freeWorker, taskInfo, workerPoolWorkerFlag } from './constants';
 
 import type {
   WorkerCallback,
@@ -81,7 +81,9 @@ export class WorkerPool extends EventEmitter {
   }
 
   private addNewWorker() {
-    const worker: WorkerWithTaskInfo = new Worker(this.filePath);
+    const worker: WorkerWithTaskInfo = new Worker(this.filePath, {
+      workerData: workerPoolWorkerFlag
+    });
 
     worker.on('message', (result) => {
       worker[taskInfo]?.done(null, result);

packages/terser/src/worker.ts

@@ -1,9 +1,11 @@
-import { isMainThread, parentPort } from 'worker_threads';
+import { isMainThread, parentPort, workerData } from 'worker_threads';
 
 import { hasOwnProperty, isObject } from 'smob';
 
 import { minify } from 'terser';
 
+import { workerPoolWorkerFlag } from './constants';
+
 import type { WorkerContextSerialized, WorkerOutput } from './type';
 
 /**
@@ -22,7 +24,7 @@ function isWorkerContextSerialized(input: unknown): input is WorkerContextSerial
 }
 
 export function runWorker() {
-  if (isMainThread || !parentPort) {
+  if (isMainThread || !parentPort || workerData !== workerPoolWorkerFlag) {
     return;
   }