fix(AsyncSubject): do not allow change value after complete

closes #1800

spec/subjects/AsyncSubject-spec.ts

@@ -79,6 +79,21 @@ describe('AsyncSubject', () => {
  expect(observer.results).to.deep.equal([2, 'done']);
  });
 
+ it('should not allow change value after complete', () => {
+ const subject = new AsyncSubject();
+ const observer = new TestObserver();
+ const otherObserver = new TestObserver();
+ subject.subscribe(observer);
+
+ subject.next(1);
+ expect(observer.results).to.deep.equal([]);
+ subject.complete();
+ expect(observer.results).to.deep.equal([1, 'done']);
+ subject.next(2);
+ subject.subscribe(otherObserver);
+ expect(otherObserver.results).to.deep.equal([1, 'done']);
+ });
+
  it('should not emit values if unsubscribed before complete', () => {
  const subject = new AsyncSubject();
  const observer = new TestObserver();

src/AsyncSubject.ts

@@ -6,11 +6,9 @@ import {Subscription} from './Subscription';
  * @class AsyncSubject<T>
  */
 export class AsyncSubject<T> extends Subject<T> {
- value: T = null;
-
- hasNext: boolean = false;
-
- hasCompleted: boolean = false;
+ private value: T = null;
+ private hasNext: boolean = false;
+ private hasCompleted: boolean = false;
 
  protected _subscribe(subscriber: Subscriber<any>): Subscription {
  if (this.hasCompleted && this.hasNext) {
@@ -26,8 +24,10 @@ export class AsyncSubject<T> extends Subject<T> {
  }
 
  next(value: T): void {
- this.value = value;
- this.hasNext = true;
+ if (!this.hasCompleted) {
+ this.value = value;
+ this.hasNext = true;
+ }
  }
 
  complete(): void {