为什么我在Angular 6中会出错？

Question

import { EventEmitter, Injectable } from '@angular/core';

@Injectable()
export class PingOnActionListenerService {
    removingListener = new EventEmitter();

    removeListener(): void {
        this.removingListener.emit();
    }

this._pingOnActionListenerService.removeListener();

    ngOnInit() {
        this._pingOnActionListenerService.removingListener.subscribe(this.deactivatelistener());
    }

    deactivatelistener() {
        window.removeEventListener('click', this.pingIfLastPingIsOld);
    }

core.js:1671错误类型错误：generatorOrNext不是SafeSubscriber.SchedulerFn[as_next](core.js:3565)在SafeSubscriber.push../node_modules/rxjs/_esm5/internal/subscriber.js.safeSubscriber.__tryRunsub(subscriber.js:195)在SafeSubscriber.push./node_modules/rxjs/_esm5/internal/subscriber.js.safeSubscriber.next(Subscriber.js:133)在subscriber.push./node_modules/rxjs/_esm5/internal/subscriber.js.subscriber.next_next(subscriber.js:77)位于subscriber.push./node_modules/rxjs/_esm5/internal/subscriber.js.subscriber.next(subscriber.js:54)位于eventemitter.push./node_modules/rxjs/_esm5/internal/subject.js.subject.next(subject.js:47)位于eventemitter.push./node_modules/@angular/core/fesm5/core.js.eventemitter.emit(core.js:3537)位于CatchSubscriber.Selector上的PingOnActionListenerService.RemoveListener(ping-on-Action-Listener.Service.ts:19)（日志记录-Interceptor.ts:45)在catchsubscriber.push../node_modules/rxjs/_esm5/internal/operators/catcherror.js.catchsubscriber.error（catcherror.js:33)

Answer 1

您不应该在服务中使用EventEmitter，它应该只用于组件绑定和@output()。您应该将其重新设计为subject/observable:

export class PingOnActionListenerService {
  _removingListener = new BehaviorSubject<boolean>(false);

  removeListener(): void {
    this._removingListener.next(true);
  }

  get removeListener$(): Observable<boolean> {
    return this._removingListener.asObservable()
      .pipe(filter(val => val));
  }
}

在组件B中使用：

ngOnInit() {
  this._pingOnActionListenerService.removeListener$
   .subscribe(() => {
     this.deactivatelistener();
   });
}

不要忘记在组件ngondestroy中取消订阅。