Delete index at array in Firestore

Question

I got this data in my document:

I want to delete index 0. How do I do this? This should do the trick I thought:

    db.collection("data").document("free").updateData(["deleteme.deletemee.0" : FieldValue.delete()]) { (errr) in
        print(errr)
    }

But the errr prints nil, and nothing is removed. When getting the document I noticed something strange about the data when using this code:

    db.collection("data").document("free").getDocument { (doc, err) in
        guard let _doc = doc,
            doc?.exists ?? false else{ return }
        print(_doc.data())
    }

This prints out:

["deleteme": {
    deletemee =     (
        1 //this is the value for the key, but where is my key?! :(
    );
}]

I cannot see the key, where is it? How to delete something at an index in Firestore? Thanks.

ranjjose · Accepted Answer · 2018-08-12 08:07:50Z

32

Array operations have finally been supported. Deletion, addition, etc. are supported via the value (not the index) now:

At the moment, there are a few bugs at the moment though as this one I encountered.

The dev blog here:

answered Aug 12, 2018 at 8:07

ranjjose

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3 Comments

Sampath Over a year ago

This MUST be the answer now.

J. Doe Over a year ago

@Sampath yea times have changed, I made this answer now the accepted answer

iCantC Over a year ago

In case if values are double, then arrayRemove needs to match the value up to last precision : (

Sam Stern · Accepted Answer · 2017-10-14 00:05:33Z

5

It is not currently possible to modify individual elements of an array stored in Cloud Firestore.

If you stored the data as a map (the keys dont matter) like this:

{
  name: "sam",
  things: {
    one: "value",
    two: "value"
  }
}

Then you can delete individual elements like this:

// Delete the things.one data
db.collection("whatever").document("whatever").updateData([
    "things.one": FieldValue.delete(),
]) { err in
    if let err = err {
        print("Error updating document: \(err)")
    } else {
        print("Document successfully updated")
    }
}

Now the data will look like this:

{
  name: "sam",
  things: {
    two: "value"
  }
}

answered Oct 14, 2017 at 0:05

Sam Stern

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2 Comments

J. Doe Over a year ago

>:( hmm ok so arrays are pretty useless at this time since they can not be changed...

Sam Stern Over a year ago

Yes right now they're not terribly useful, but these are just Beta limitations and in the future we will have better support for arrays / array queries.

Danish · Accepted Answer · 2020-11-12 07:43:49Z

-1

export const deleteArrayIndex = (collectionName, id, index) => {
    db.collection(collectionName).doc(id).update(
        { [index]: firebase.firestore.FieldValue.delete() }
    ).then(function () {
        console.log(index + "  is deleted");
    }).catch(function (error) {
        console.error("Error removing document: ", error);
    });
}

answered Nov 12, 2020 at 7:43

Danish

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1 Comment

Elletlar Over a year ago

Hi Danish. Welcome to Stack Overflow. While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value. How to Answer. Kind Regards.

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