chore: use Subject instead of an array of observers

Author: IKatsuba

projects/workers/src/worker/classes/web-worker.ts

@@ -1,14 +1,13 @@
-import {EMPTY, fromEvent, merge, Observable, Observer} from 'rxjs';
-import {take, tap} from 'rxjs/operators';
+import {EMPTY, fromEvent, merge, Observable, Subject} from 'rxjs';
+import {take, takeUntil, tap} from 'rxjs/operators';
 import {WORKER_BLANK_FN} from '../consts/worker-fn-template';
 import {TypedMessageEvent} from '../types/typed-message-event';
 import {WorkerFunction} from '../types/worker-function';
 
 export class WebWorker<T = any, R = any> extends Observable<TypedMessageEvent<R>> {
     private readonly worker: Worker | undefined;
     private readonly url: string;
-    private isStopped: boolean;
-    private observers: Observer<TypedMessageEvent<R>>[];
+    private readonly destroy$: Subject<void>;
 
     constructor(url: string, options?: WorkerOptions) {
         let worker: Worker | undefined;
@@ -25,7 +24,7 @@ export class WebWorker<T = any, R = any> extends Observable<TypedMessageEvent<R>
 
             if (error) {
                 subscriber.error(error);
-            } else if (this.isStopped) {
+            } else if (this.destroy$.isStopped) {
                 subscriber.complete();
             } else if (worker) {
                 eventStream$ = merge(
@@ -35,19 +34,15 @@ export class WebWorker<T = any, R = any> extends Observable<TypedMessageEvent<R>
                     fromEvent<ErrorEvent>(worker, 'error').pipe(
                         tap(event => subscriber.error(event)),
                     ),
-                );
-
-                this.observers.push(subscriber);
+                ).pipe(takeUntil(this.destroy$));
             }
 
-            return eventStream$.subscribe();
+            eventStream$.subscribe().add(subscriber);
         });
 
         this.worker = worker;
         this.url = url;
-
-        this.isStopped = false;
-        this.observers = [];
+        this.destroy$ = new Subject<void>();
     }
 
     static fromFunction<T, R>(
@@ -82,7 +77,7 @@ export class WebWorker<T = any, R = any> extends Observable<TypedMessageEvent<R>
     }
 
     terminate() {
-        if (this.isStopped) {
+        if (this.destroy$.isStopped) {
             return;
         }
 
@@ -92,13 +87,8 @@ export class WebWorker<T = any, R = any> extends Observable<TypedMessageEvent<R>
 
         URL.revokeObjectURL(this.url);
 
-        this.isStopped = true;
-        this.observers.forEach(observer => {
-            if (!observer.closed) {
-                observer.complete();
-            }
-        });
-        this.observers = [];
+        this.destroy$.next();
+        this.destroy$.complete();
     }
 
     postMessage(value: T) {