Firestore push item to nested Array

Question

I have Database like this

now I need to push items to directors array.

I tried this code

Firestore()
    .collection('notices')
    .doc(item.id)
    .set({readBy: {directors: [user.id]}}, {merge: true});

but it replace the existing items in directors array.

How to push items to directors array without replacing existing items ?

Does this answer your question? [How to update an "array of objects" with Firestore?](https://stackoverflow.com/questions/46757614/how-to-update-an-array-of-objects-with-firestore) — Tahir Yasin, Jul 20 '20 at 07:20
No that is not. That is Array of objects. my one is object of arrays — Priyashan Jayasankha, Jul 20 '20 at 07:21

score 1 · Answer 1 · answered Jul 20 '20 at 08:28

1

You need to use the arrayUnion function for this:

Firestore()
.collection('notices')
.doc(item.id)
.set({readBy: {directors: FieldValue.arrayUnion([user.id])}}, {merge: true});

answered Jul 20 '20 at 08:28

l1b3rty

1 Answers1