How to delete a field in a Firestore Document?

Question

How to delete a Document Field in Cloud Firestore? ... I'm using the code below but I can not.

this.db.doc(`ProfileUser/${userId}/followersCount/FollowersCount`).update({ 
[currentUserId]: firebase.firestore.FieldValue.delete()})

Is it possible, and if so, how?

Answer 1

This worked for me. (also worked to delete field with null value)

document.ref.update({
  FieldToDelete: admin.firestore.FieldValue.delete()
})

Answer 2

With Firebase Version 9 (Feb, 2022 Update):

If there is the collection "users" having one document(dWE72sOcV1CRuA0ngRt5) with the fields "name", "age" and "sex" as shown below:

users > dWE72sOcV1CRuA0ngRt5 > name: "John", 
                               age: 21, 
                               sex: "Male"

You can delete the field "age" with this code below:

import { doc, updateDoc, deleteField } from "firebase/firestore";

const userRef = doc(db, "users/dWE72sOcV1CRuA0ngRt5");

// Remove "age" field from the document
await updateDoc(userRef, {
  "age": deleteField()
});

users > dWE72sOcV1CRuA0ngRt5 > name: "John",  
                               sex: "Male"

You can delete multiple fields "age" and "sex" with this code below:

import { doc, updateDoc, deleteField } from "firebase/firestore";

const userRef = doc(db, "users/dWE72sOcV1CRuA0ngRt5");

// Remove "age" and "sex" fields from the document
await updateDoc(userRef, {
  "age": deleteField(),
  "sex": deleteField()
});

users > dWE72sOcV1CRuA0ngRt5 > name: "John"

Answer 3

For some reason the selected answer (firebase.firestore.FieldValue.delete()) did not work for me. but this did:

Simply set that field to null and it will be deleted!

// get the reference to the doc
let docRef=this.db.doc(`ProfileUser/${userId}/followersCount/FollowersCount`);

// remove the {currentUserId} field from the document
let removeCurrentUserId = docRef.update({
    [currentUserId]: null
});

Answer 4

carefully using this admin.firestore.FieldValue.delete() Because query doesn't work if you try to delete not available field on the document.

So, I think it's better to set null

this.db.doc(`ProfileUser/${userId}/followersCount/FollowersCount`).update({ 
[currentUserId]: null})

OR

await db.doc(`ProfileUser/${userId}/followersCount/FollowersCount`)
            .set({[currentUserId]: null}, { merge: true })