CODEWITHSUNDEEP
angularobservable
Priyashan Jayasankha
Priyashan Jayasankha

Reputation: 302

Convert observable to a variable

I am retriving some data from firebase via observable in valueChanges method.

this.authService.getUser().subscribe(
      user => {
        this.studentDetailsService.readStudentDatabase( user.uid ).subscribe( temp => {
          this.student = temp as StudentDetails ;
        });
      }
    );

but i cant use this.student objects out side the Observable like this

this.authService.getUser().subscribe(
      user => {
        this.studentDetailsService.readStudentDatabase( user.uid ).subscribe( temp => {
          this.student = temp as StudentDetails ;
        });
      }
    );

    this.name = this.student.firstName;

when im doing this console shows this.name is undefined.

how to solve this ?? how can i use those retrived values outside the observable ?

Upvotes: 1

Views: 415

Answers (1)

Martin
Martin

Reputation: 16292

You can do something like this

studenDetails$ = this.authService.getUser().pipe(
  switchMap(user => 
     this.studentDetailsService.readStudentDatabase(user.id)));

Then you can output the student details in your template using the async pipe rather than using subscribe. 

{{ studenDetails$ | async | json }}

You can do something like the following, but I would recommend using using the above solution instead

this.authService.getUser().pipe(
  switchMap(user => 
     this.studentDetailsService.readStudentDatabase(user.id).pipe(
       tap(student => this.student = student),
       map(student => student.firstName),
       tap(firstName => this.firstName = firstName))).subscribe();

This will set the class field firstName to the students first name.

Upvotes: 1

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