How to use arrayUnion in Firestore using Angular

Issue

I have been trying to learn using Firestore and could not find the documentation helpful at all in the case AngularFire since using FieldValue just throws an error as "FieldValue does not exist".

const userRef = this.firestore.collection('users').doc(email);

userRef.update({
  lessonsWatched: this.firestore.FieldValue.arrayUnion(newLessonObject)
})

What am I missing here?

Solution

import { arrayUnion } from '@angular/fire/firestore';
this.firestore.doc(...).update({ field: arrayUnion(...) });

Similar should work for other FieldValue functions, such as increment.

See:

• https://github.com/angular/angularfire/issues/2036#issuecomment-1337755616
• https://stackoverflow.com/a/74691835

Answered By - Doug Stevenson