RXJS Observable doSomething onComplete [英] RXJS Observable doSomething onComplete

问题描述

我想使用 RXJS Observable.基本上它工作正常，但我不仅需要在 observer.next() 和 observer.complete() 被调用时做出反应.如何获得 RXJS Observable 的 OnComplete 事件?在我看来，RXJS 文档令人困惑.

I would like to use the RXJS Observable. Basically it works fine, but I need not just to react when observer.next() but also when observer.complete() is called. How do I get the event of OnComplete of an RXJS Observable? In my opinion the RXJS doc is confusing.

export class Service {
    myMethod():Observable<any> {
        return Observable.create((observer:any) => {
        for(let i=0; i<10; i++) {
         observer.next(i);
        }
        if(true==true) {
            // this event I need
            observer.complete();
        } else {
            observer.error(xhr.response);
        }
    }
}

export class Component() {
    // constructor etc.

    doSome() {
        this.service.myMethod()
        // Here I would like to get OnComplete event
          .catch(this.handleError)
          .subscribe((num:any) => {
            console.log(num);
        });
    }
}

推荐答案

subscribe 方法接受三个回调.最后一个是完整的事件.

The subscribe method accepts three callbacks. The last one is for the complete event.

doSome() {
  this.service.myMethod()
      .subscribe((num:any) => {
        console.log(num);
      }, (err) => {
        this.handleError(err);
      }, () => { // <----
        this.handleComplete();
      });
}

您也可以为此利用 finally 运算符.

You could also leverage the finally operator for this.

doSome() {
  this.service.myMethod()
      .catch(this.handleError)
      .finally(this.handleComplete) // <----
      .subscribe((num:any) => {
        console.log(num);
    });
}

注意:如果我们有错误，这两个示例之间存在差异:如果我们添加 console.logs 我们会在第一种情况下看到只打印handleError

note: there is a difference between the two examples in case we have errors: if we would add console.logs we would see that in the first case only handleError is printed

-> handleError

第二种情况

-> handleError
-> finally

换句话说，finally 总是被调用，而 complete 则不是.

in other words finally is always called, were complete is not.

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