Angular2 return Observable<Response> from wrapped Html.get

Question

I need to wait for this observable to return (simplified):

assembleOptions(options?: RequestOptionsArgs): Observable<boolean> {

    let auth = this._cookieService.get(this.auth);

    if (auth === undefined || auth === null) {
        this._http.get('/someValue').map(x => {
            //do something with x
            return Observable.of(true);
        })
    } else {
        return Observable.of(true);
    }
}

This appears to return an Observable<true> which doesn't really matter, as I am not using it, I just need to wait for it, then I try to use it within this:

public get(url: string, options?: RequestOptionsArgs): Observable<Response> {
  return this.assembleOptions(options).map(x => {
      return this._http.get(url, this.options);
  });
}

Where this._http is from

import { Http, Response, Headers, RequestOptionsArgs } from '@angular/http';

Which does not work, it is returning an Observable<Observable<Response>>

Type 'Observable<Observable<Response>> is not assignable to type 'Observable<Response>'

What am I missing here? I have tried casting all over the place to no avail.

Igor Igor · Accepted Answer · 2017-10-25T15:25:02

You want switchMap instead of map

return this.assembleOptions(options).switchMap(x => {
      return this._http.get(url, this.options);
  });

From the switchMap documentation

Map to observable, complete previous inner observable, emit values

Angular2 return Observable<Response> from wrapped Html.get

1 Answers