Use a promise in Angular HttpClient Interceptor

Question

Can I use promise within HttpInterceptor? For example:

export class AuthInterceptor implements HttpInterceptor{
this.someService.someFunction()
         


        

Answer 1

My turn (Thanks to Jota.Toledo and Capripio) :

1) Switch "fromPromise" to "from" --> fromPromise does not exist on type Observable

2) Fix 'application/json' quote

import { Observable, from } from 'rxjs';
import { switchMap } from 'rxjs/operators';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

  constructor(private authService: AuthService){}

  intercept(req: HttpRequest, next: HttpHandler): Observable> {

      return from(this.authService.getToken()).pipe(
        switchMap(token => {
            const headers = req.headers
                .set('Authorization', 'Bearer ' + token)
                .append('Content-Type', 'application/json');
            const reqClone = req.clone({
                headers
            });
            return next.handle(reqClone);
        }));
   }
}

My version of RxJs: "6.2.2" Hope that helped !