Angularfire2 get single document without listener

Question

I'm using angularfire2 v6 and angular 11. I'm simply trying to get a single document from the users collection based on their email. I don't want to use valueChanges() or snapshotChanges() as the user object won't be updated, and if it is, I don't care to get realtime updates. I just want to get the data once when the user navigates to their profile. I've seen that you should be able to use get() instead of the aforementioned methods, but I can't get anything to work correctly.

Doing this works fine:

let query = (this.firestore.collection('users', ref => ref.where('email', '==', res.email)).valueChanges());
// subscribe to changes
query.subscribe(queriedItems => {
  this.item = queriedItems[0];
  this.firstName = this.item.firstname;
  this.lastName = this.item.lastname;
  this.email = this.item.email;
  this.role = this.item.role;
  this.lead = !!this.item.lead;
});

But again, doesn't valueChanges() by nature keep listening for updates? I don't want to do that. And replacing .valueChanges() with .get() means I can't subscribe, and using toPromise().then() seems to just return junk and not the actual document.

Answer 1

Couldn't figure out how to make the get() work at all, but I did find a workaround by setting it to a subscription, then unsubscribing once you get the data.

this.fireAuth.currentUser.then((res) => {

  let query = (this.firestore.collection('users', ref => ref.where('email', '==', res.email)).valueChanges());
  // subscribe to changes
  this.profileSubscription = query.subscribe(queriedItems => {
    this.item = queriedItems[0];
    this.firstName = this.item.firstname;
    this.lastName = this.item.lastname;
    this.email = this.item.email;
    this.role = this.item.role;
    this.lead = !!this.item.lead;

    //Unsubscribe here if you don't want an active listener to show changes
    this.profileSubscription.unsubscribe();
  });

});