Question

我试图取消订阅ngOnDestroy中的一个observable，但它告诉我它在Observable类型中不存在。

export class AppComponent implements OnInit {
  public caseData;

  constructor(private _caseService: CaseService,
              private _title: Title,
              private _metaService: Meta) { }

  ngOnInit(): void {
    this._caseService.GetCaseData('en', 'English');
    this._caseService.caseData$.subscribe(res => { this.caseData = res },
      (error) => { console.log(error) });
  }

  ngOnDestroy() {
    this._caseService.caseData$.unsubscribe(); //says it does not exist
  }
}

Answer 1

订阅本身已退回。

  subscription: Subscription;

  ngOnInit(): void {

    this._caseService.GetCaseData('en', 'English');

    this.subscription = this._caseService.caseData$.subscribe(res => { this.caseData = res },
      (error) => { console.log(error) });

  }
  ngOnDestroy(){
    this.subscription.unsubscribe(); 
  }

Answer 2

unsubscribe()是Subscription的方法，而不是Observable。

Answer 3

这应该有效：

export class AppComponent implements OnInit {
  public caseData;
  subscription: any;

  constructor(private _caseService: CaseService, private _title: Title, private _metaService: Meta) { }

  ngOnInit() {
    this._caseService.GetCaseData('en', 'English');
    this.subscription = this._caseService.caseData$.subscribe(res => { this.caseData = res },
      (error) => { console.log(error) });
  }

  ngOnDestroy(){
    this.subscription.unsubscribe();
  }
}

Answer 4

为了更好地处理订阅，我建议您检查这两个链接：

https://medium.com/thecodecampus-knowledge/the-easiest-way-to-unsubscribe-from-observables-in-angular-5abde80a5ae3

和

Angular/RxJs When should I unsubscribe from `Subscription`

Observable＆lt;＆gt;类型上不存在取消订阅？

4 个答案: