Passing variable to firestore where query (Angular)

Question

I am trying to query a schedule collection where a field in the document = the users id, but i am getting this error: "Function Query.where() requires a valid third argument, but it was undefined."

     userId;
     uid;
     sched: Observable<ScheduleModel[]>;

The ngOnInit()

  ngOnInit() {
    this.userId = this.afAuth.authState.subscribe(user => {
      this.uid = user.uid;
    });
    this.getSched();
  }

getSched() {
  this.sched = this.afs.collectionGroup<ScheduleModel>('schedule', ref => ref.where('uid', '==', this.uid)).valueChanges();
}

this.uid in the query is giving me the trouble but:

When i put the actual user uid 'iq6DkETjgMSMIdxw9cvLEzbf9Fr2' rather than this.uid, it works.
In my template file when i put use {{ uid }} and it prints the correct id, so it is not actually undefined.

ThienLD · Accepted Answer · 2020-08-26 06:27:07Z

1

Try this

ngOnInit() {
let self = this;
this.userId = this.afAuth.authState.subscribe(user => {
  self.uid = user.uid;
});
this.getSched();
}

this in your this.uid is not in the same scope as you were using {{uid}}

answered Aug 26, 2020 at 6:27

ThienLD

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4 Comments

ThienLD Over a year ago

try the same thing with getSched() below, declare something like let self = this and use self.uid

balance85 Over a year ago

Thanks for the reply. Still did not work, but you are correct about the scope. I created an alert box with the uid value and it gets displayed as 'Undefined' but then it still shows up in the view. I tried moving it to constructor with the same result.

ThienLD Over a year ago

@balance85 well, atleast we know what is the problem now

balance85 Over a year ago

Ah.. I figured it out. Thanks for the help.

balance85 · Accepted Answer · 2020-08-27 03:28:50Z

0

 this.userId = this.afAuth.authState.subscribe(user => {
    this.uid = user.uid;
    **this.sched = this.afs.collectionGroup<ScheduleModel>('schedule', ref => ref.where('uid', '==', this.uid)).valueChanges();
  });

moving the assignment of **this.sched seemed to do the trick.

answered Aug 27, 2020 at 3:28

balance85

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