Myujth

I have a function that is currently working. When calling this function, it will set a value in the component. (user.userImage)

getLoggedInUserPhoto() 
this.adalService.acquireToken('https://graph.microsoft.com')
 .subscribe(token => 
 let header = new HttpHeaders().set('Authorization', 'Bearer ' + token).set('Content-Type', 'image/jpeg');
 this.imageService.getImage('https://graph.microsoft.com/v1.0/me/photo/$value', header)
 .subscribe(blob => 
 this.imageService.getImageUrlFromBlob(blob)
 .then(res => 
 this.user.userImage = res;
 )
 )
 );

I am trying to do the same thing with a new function, except I want the function to return the value instead of setting a value in the component. I have searched all over and most likely I am using the wrong search terms. However, here is a pass at what I am trying to achieve

getPhoto(email: string): string 
return this.adalService.acquireToken('https://graph.microsoft.com')
 .subscribe(token => 
 let header = new HttpHeaders().set('Authorization', 'Bearer ' + token).set('Content-Type', 'image/jpeg');
 this.imageService.getImage('https://graph.microsoft.com/v1.0/users/'+email+'/photo/$value', header)
 .subscribe(blob => 
 this.imageService.getImageUrlFromBlob(blob)
 .then(res => 
 return res;
 )
 )
 );

I would suggest you to use switchMap ,since switchMap operator will wait for the response of the first request to arrive before firing the second request.

return this.http.get('https://graph.microsoft.com')
 .switchMap(res1 => 
 // use res1 to further control param of the second call
 this.http.get(''https://graph.microsoft.com/v1.0/users/'+email+'/photo/$value', header')
 )
 .subscribe(res2 => 
 //do stuff with the second response
 )

You should use merge map in the pipe. Then you can do what you are trying to do. when using merge map it wait one subscription to finish and then you can use it response in next action.

return this.adalService.acquireToken('https://graph.microsoft.com').
 pipe(
 mergeMap(res => 
 this.http.get(''https://graph.microsoft.com/v1.0/users/'+email+'/photo/$value', header')
 )
 ).subscribe(res => 
 //this "res" give you the second request respond
 )