Load user from id_token or provide a means to populate the user$ observable

[thomaux]

Correct me if I'm wrong, but I believe currently the only way to make the user$ observable return a value is to call the loadUserInfo method?

Would it be possible to allow loading this info based on the returned id_token or alternatively to provide a way to set the value of the underlying _userSubject Subject?

FYI: My current solution is to hook into the events, then get the user data based on the token and either:
a) "hack" into the AuthService and access the private Subject or
b) Move everything in a separate service, which exposes its own user$ observable.

I went for option b:

import { Injectable } from '@angular/core';
import { TokenResponse } from '@openid/appauth';
import { AuthService } from 'ionic-appauth';
import { filter, Observable, Subject, switchMap, take, tap } from 'rxjs';

export interface User {
  name: string;
}

@Injectable({
  providedIn: 'root'
})
export class UserService {
  private readonly userSubject: Subject<User | undefined> = new Subject();

  constructor(authService: AuthService) {
    authService.initComplete$.pipe(
      filter(complete => complete),
      switchMap(() => authService.isAuthenticated$),
      filter(isAuthenticated => isAuthenticated),
      take(1),
      switchMap(() => authService.token$),
      tap(tokens => {
        this.userSubject.next(getUserFromTokens(tokens));
      }),
    ).subscribe();
  }

  get user$(): Observable<unknown> {
    return this.userSubject.asObservable();
  }
}

function getUserFromTokens(tokens: TokenResponse): User | undefined {
  if (!tokens.idToken) {
    return;
  }
  return JSON.parse(Buffer.from(tokens.idToken.split('.')[1], 'base64').toString('ascii')) as User;
}