Question

如何使嵌套的Observable中的内部Observable错误或成功识别外部Observable？

为什么onNext和onCompleted在内部Observable内未定义？

public updateDocument(item: Document): Observable<any> {
    this.firstUseOfflineContainer();
    let afiEdit = this.offlineData.afi.edit;

    //outer observable
    return Observable.create(observer => {
        //inner observable
        this.dataService.updateRequest(item).subscribe(
            (next) => {
                console.log("ok");
            },
            (err) => {                
                afiEdit.headers.push(item);
                //how to throw error to outer observable
            },
            () => {
                observer.onNext(item);
                observer.onCompleted();
            }
        );

        return () => console.log('cleanup message')
    });
}

Answer 1

我的理解是，当内部observable失败时，你的目标只是在外部observable中抛出一个错误。

所以代码看起来像这样：

//Define the inner observable (probably an http call in your case)
//I mocked your call failing or passing with a random 50/50 chance
var innerObservable = new Rx.Observable(observer => {
  var didMockCallFail = Math.random() < .5; 
  if(didMockCallFail){
    console.log('Inner observable call failed');
    observer.error(new Error('Call failed!'));
  } else {
    console.log('Inner observable call returned data');
    observer.next({lolData: 'I am data'}); 
  }
})

//define the outer observable which just calls the inner observable
var outerObservable = new Rx.Observable(observer => {
  innerObservable.subscribe(
    data => observer.next(data),
    err => observer.error(err)
  )
});

outerObservable.subscribe(
  next => console.log('Got data!'),
  err => console.error('lol fail')
);

此外，请注意，如果要将变量传递给Observable并使该代码可重用/避免全局范围，则可以使用生成器函数，例如

function makeObs(someParam){
  return new Rx.Observable(observer => {
    observer.next(someParam);
  })
}

如果您有任何疑问，请与我们联系。

如何使外部Observable能够从嵌套的Observable中的内部Observable错误或成功中识别出来？

1 个答案: