Merging http observables using forkjoin

Question

I\'m trying to avoid nested observables by using forkjoin. The current (nested) version looks like this:

  this.http.get(\'https://testdb1.fireb         


        

Answer 1

Try to use combineLatest instead of forkJoin :

With combineLatest :

const combined = Observable.combineLatest(
  this.http.get('https://testdb1.firebaseio.com/.json').map((res: Response) => res.json()),
  this.http.get('https://testdb2.firebaseio.com/.json').map((res: Response) => res.json())
)

combined.subscribe(latestValues => {
    const [ data_changes , data_all ] = latestValues;
    console.log( "data_changes" , data_changes);
    console.log( "data_all" , data_all);
});

You can also handle it by forkJoin , but forkJoin will return data when all calls are finished and return result , but in combineLatest When any observable emits a value, emit the latest value from each.

With forkJoin :

const combined = Observable.forkJoin(
  this.http.get('https://testdb1.firebaseio.com/.json').map((res: Response) => res.json()),
  this.http.get('https://testdb2.firebaseio.com/.json').map((res: Response) => res.json())
)

combined.subscribe(latestValues => {
    const [ data_changes , data_all ] = latestValues;
    console.log( "data_changes" , data_changes);
    console.log( "data_all" , data_all);
});

Call both and check the console log , you will get idea.