object 无效，应为 stream

Question

I am getting this error

Type 'never' must have a 'Symbol.iterator' method that returns an iterator.

I know that error is related to my if statement in the code below (drivers.service.ts)

 export class DriversService { user: User; comp = ''; constructor(private db: AngularFirestore, private auth: AuthService, private afAuth: AngularFireAuth) { } getUsers() { return this.auth.user.pipe( take(1), map(user => { // user['company']; this.comp = user['company']; return user['company']; }) ) } findUser(value) { if(this.comp.length <= 0){ return this.getUsers().subscribe(user => { this.comp = user; console.log('Bye', this.comp) return this.comp; }); } let email = this.db.collection(`companies/${this.comp}/users`, ref => ref.where('email', '==', value)).valueChanges({ idField: 'id' }).pipe( take(1) ); let name = this.db.collection(`companies/${this.comp}/users`, ref => ref.where('name', '==', value)).valueChanges({ idField: 'id' }).pipe( take(1) ); return [email, name]; }

And accutal error is showing in add-driver.page.ts in forkJoin()

 export class AddDriverPage implements OnInit { users = []; participant = ''; form: FormGroup; constructor(private driverService: DriversService, private loadingCtrl: LoadingController, private auth: AuthService) { } ngOnInit() { } addDriver() { let obs = this.driverService.findUser(this.participant); forkJoin(obs).subscribe(res => { for (let data of res) { if (data.length > 0) { this.users.push(data[0]); } } console.log('it works:', this.participant) this.participant = ''; }); } }

So how do I solve this issue?

Answer 1

Change in your service function:

if (this.comp.length <= 0) {
      return [this.getUsers().pipe(map(user => {
        this.comp = user;
        console.log('Bye', this.comp);
        return this.comp;
       }))];
    }

Then in your component:

addDriver() {
    const obs = this.driverService.findUser(this.participant);

    forkJoin(obs).subscribe(res => {
      if (!res || !res.length) {
        return console.log('Got undefined');
      }
      for (let data of res) {
        if (data.length > 0) {
          this.users.push(data[0]);
        }
      }
      console.log('it works:', this.participant)
      this.participant = '';
    }, error => {
   console.log('Here you got an error: ', error);
});
  }