cothema / ionic-universal-firebase-login

import { Injectable } from '@angular/core';

import * as firebase from 'firebase';

import { Observable, Subscriber } from 'rxjs';

import { FirebaseUserModel, UserModel } from '..';

import { IStorageProvider } from './i-storage-provider';

@Injectable({

    providedIn: 'root',

})

export class InMemoryStorage<User extends UserModel = UserModel>

    implements IStorageProvider<User> {

    private userData: any;

    private subscribers: Subscriber<unknown>[] = [];

    public async updateStoredDataByUser(user: User): Promise<void> {

        this.userData = user;

        this.onUserDataChanged();

    }

    public updateStoredDataByFirebaseUser(firebaseUser: firebase.User): Promise<void> {

        if (firebaseUser.uid) {

            const data = new FirebaseUserModel({

                displayName: firebaseUser.displayName,

                email: firebaseUser.email,

                photoURL: firebaseUser.photoURL,

                uid: firebaseUser.uid,

            });

            Object.assign(this.userData, data);

            return new Promise(resolve => resolve());

        } else {

            throw new Error('Firebase user has no UID.');

        }

    }

    private onUserDataChanged() {

        for (const subscriber of this.subscribers) {

            subscriber.next(this.userData);

        }

    }

    public fetchUser(): Promise<User | unknown | null> {

        return this.subscribeUser().toPromise();

    }

    public subscribeUser(): Observable<User | unknown | null> {

        return new Observable(subscriber => {

            this.subscribers.push(subscriber);

            subscriber.next(this.userData);

        });

    }

}