Firestore - Delete a field inside an object

Question

I'm using Firestore and I would like to delete a field that is in a specific object. I can delete a field in a document thanks to:

fieldName: firebase.firestore.FieldValue.delete()

But if I have an object like:

songList {
songName1: "HelloWorld",
songName2: "AnotherSong",
songName3: "andTheLastOne"
}

In order to delete the field songName3, I won't be able to do something like:

songList.songName3: firebase.firestore.FieldValue.delete()

Is there a way to delete a field inside an object? Or should I delete the whole object, rebuild it without the 3rd field and save it?

Thanks in advance,

Answer 1

The "dot notation" with the special "FieldValue.delete()" should work.

Try this:

    Map<String, Object> deleteSong = new HashMap<>();
    deleteSong.put("songList.songName3", FieldValue.delete());

    FirebaseFirestore.getInstance()
        .collection("yourCollection")
        .document("yourDocument")
        .update(deleteSong);

It worked for me.

See: https://firebase.google.com/docs/firestore/manage-data/delete-datahttps://firebase.google.com/docs/firestore/manage-data/add-data

Answer 2

This work for me in general

firebase
  .firestore()
  .collection('collection-name')
  .doc('doc-id')
  .set({ songlist : {
    [songName]: firebase.firestore.FieldValue.delete()
  }
  }, { merge: true });

Answer 3

Found this topic today and want to add my solution. I am using the dot notation. The following will remove the specific song from the songlist by using firestore.FieldValue.delete(); . I am using the Node.js firebase-admin package written in TypeScript:

import * as admin from 'firebase-admin';
export async function removeSong(trackId: string, song: string) {
    try {
        const updates = {};
        // Dot Notation - will delete the specific song from songList
        updates[`songList.${song}`] = admin.firestore.FieldValue.delete();
        // Not necessary, but it's always a good practice
        updates['updatedAt'] = admin.firestore.FieldValue.serverTimestamp();

        await firestore.collection('songs').doc(trackId).update(updates);
        return true
    } catch (error) {
        return null;
    }
}

Answer 4

It did not allow me to comment above, but Manuel Borja's solution works and is pretty clean. Here is how I used it:

db.collection("coolcollection")
  .doc(id)
  .set(
    {
      users: {
        [firebase.auth().currentUser
          .email]: firebase.firestore.FieldValue.delete(),
      },
    },
    { merge: true }
  );

A few things to add: this works when the given field of the map exists and when it does not exist.

Answer 5

I had the same issue from Android using Kotlin, and I solved it with dot notation as well. For Android Kotlin users, that is:

 val songName: String = "songName3"
 val updatesMap = HashMap<String, Any>()
 updatesMap["songList.${songName}"] = FieldValue.delete()
 FirebaseFirestore.getInstance()
                  .collection("Your Collection")
                  .document("Your Document")
                  .update(updatesMap)

Hope this helps!

Answer 6

Simpler approach to handle maps/object

db.collection('Users').doc('key')
        .update({
            'products.keytext' : firebase.firestore.FieldValue.delete()
        })
        .then(() => {
            console.log('Success');
        })
        .catch((e) => {
            console.log('Error---->', e);
        });

This will remove object with a key keytext from products map.

Answer 7

The new recommended way is to use the exported method deleteField:

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

// Remove the 'songName3' field from the songList map in the document
await updateDoc(yourRef, {
    ['songList.songName3']: deleteField()
});

Answer 8

Caution: This does not work for Maps, only for Arrays!

You might be able to implement SongList as an array instead of a Map. Because for Arrays Firestore now has a dedicated function to remove an element from an array:

yourRef.update({
    songList: firebase.firestore.FieldValue.arrayRemove("SongName3")
});

Source: https://cloud.google.com/firestore/docs/manage-data/add-data#update_elements_in_an_array

Answer 9

Update the document with a Map which has a key you want to get deleted and value FieldValue.delete() .

var collection = FirebaseFirestore.instance.collection('collection');
collection
  .doc('document_id')
  .update(
    {
      'songList.songName3': FieldValue.delete(),
    }
);

Answer 10

const deleteField = async () => {
    const FieldValue = firestore.FieldValue;
    const itemRef = firestore().collection('COLLECTION-NAME').doc('DOCUMENT-NAME');                                
    const res = await itemRef.update(
    'ELEMENT-NAME', FieldValue.delete() //'ELEMENT-NAME' OR Object.Field which equals to Parent Field Name.
)};
e.g.
{ 
    12345: { you: 'You', me: 'Me', we: '12345' },
    56789: { you: 'You', me: 'Me', we: '56789' },
}
const res = await itemRef.update(
    object.we, FieldValue.delete() //OR '12345', FieldValue.delete()
);