Unable to employ the inequality operator while querying a collection in AngularFire

I'm facing a challenge with pulling a collection from Firebase that is not linked to the user. While I've managed to query the user's collection successfully, I am struggling to retrieve the collection that does not belong to the user using the != operator.

Below is the snippet of my code:

  // Not functioning as expected!
  eventCollection: AngularFirestoreCollection<Event> = this.angularFirestore.collection("events", ref =>
    ref.where("uid", "!=", this.firebaseAuth.auth.currentUser.uid)
  );
  eventCollection$: Observable<Event[]> = this.eventCollection.valueChanges();

  // Working as intended!
  myCollection: AngularFirestoreCollection<Event> = this.angularFirestore.collection("events", ref =>
    ref.where("uid", "==", this.firebaseAuth.auth.currentUser.uid)
  );
  myCollection$: Observable<Event[]> = this.myCollection.valueChanges();

An error message is being thrown:

ERROR in src/app/event/events.service.ts(35,22): error TS2345: Argument of type '"!"' is not assignable to parameter of type 'WhereFilterOp'.

I have tried searching for a logical operator equivalent to !=, but haven't had any luck finding it.

I would greatly appreciate any assistance with this issue!

angulartypescriptfirebasegoogle-cloud-firestoreangularfire2

Answer №1

When using Firestore, it is important to note the following guideline mentioned in the documentation:

Queries with a != clause can be handled by splitting the query into separate greater-than and less-than queries. For instance, instead of using the unsupported where("age", "!=", "30") clause, you can achieve the same results by combining two queries: one with where("age", "<", "30") and another with where("age", ">", 30).

This means that you need to compare both the '<' (less than) and '>' (greater than) conditions.

eventCollection: AngularFirestoreCollection<Event> = 
  this.angularFirestore.collection("events", ref =>
    ref.where("uid", ">", this.firebaseAuth.auth.currentUser.uid)
       .where("uid", "<", this.firebaseAuth.auth.currentUser.uid)
  );

Answer №2

It seems that the != operator is not available in Firebase. If you need to perform operations related to inequality, consider executing separate queries for < and >, and then combining the results. Another option is running a single query without the where clause, and then sorting the equal and unequal results yourself.

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