typescript RXJS Observable doSomething onComplete
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RXJS Observable doSomething onComplete
提问by Johannes
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.
我想使用 RXJS Observable。基本上它工作正常，但我不仅需要在observer.next()时作出反应，而且在observer.complete()被调用时也需要作出反应。如何获得 RXJS Observable 的 OnComplete 事件？在我看来，RXJS 文档令人困惑。
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);
});
}
}
回答by Thierry Templier
The subscribe method accepts three callbacks. The last one is for the complete event.
subscribe 方法接受三个回调。最后一个是完整的事件。
doSome() {
this.service.myMethod()
.subscribe((num:any) => {
console.log(num);
}, (err) => {
this.handleError(err);
}, () => { // <----
this.handleComplete();
});
}
You could also leverage the finallyoperator for this.
您也可以finally为此利用运营商。
doSome() {
this.service.myMethod()
.catch(this.handleError)
.finally(this.handleComplete) // <----
.subscribe((num:any) => {
console.log(num);
});
}
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 handleErroris printed
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，我们会看到在第一种情况下只handleError打印
-> handleError
in the second case
在第二种情况下
-> handleError
-> finally
in other words finallyis always called, were completeis not.
换句话说finally，总是被称为，complete不是。
回答by Natan Braslavski
As Thierry Templier answered one option is to leverage the finally/finalize(rxjs docs)
(but it's not the same as using the completeevent, see the notes)
正如 Thierry Templier 回答的那样，一种选择是利用finally/ finalize（rxjs docs）（但这与使用complete事件不同，请参阅注释）
last
最后的
Another option to do something on complete is last(rxjs/last)
完成某事的另一种选择是last（rxjs/last）
