collection('something').delete() does not recursively delete nested collections

[lockieluke]

there's a function for recursive delete in the official firestore library i do think we should add this to the library

[mikehardy]

Unfortunately that's not the way this has to work because deleting recursively requires running firestore operations in large batches (because there is a 500 document limit to deletes, and the recursive operation may total more than that...), and it's unreliable in a mobile context. It has to be done in a callable function, which is not something we can directly package for people.

But firebase has provided ample documentation and sample code for this case, and I use it myself in my apps. It works great

This is what you want

• https://firebase.google.com/docs/firestore/solutions/delete-collections
• https://github.com/firebase/snippets-node/tree/master/firestore/solution-deletes

Integrate that to your functions implementation and call it from your app as needed

[lockieluke]

deleteCollectionRecursively: (collection: FirebaseFirestoreTypes.CollectionReference<FirebaseFirestoreTypes.DocumentData>) => {
    return new Promise<void>(async (resolve, reject) => {
        const [err, data] = await to(collection.get());
        if (err) reject(err);
        if (data?.docs.length)
            await Promise.all(data.docs.map(doc => collection.doc(doc.id).delete()));

        resolve();
    })
}

dont worry mate i just found the solution it works quite well

[lockieluke]

since im using the collections for user comments i could just limit the number of comments to 500 for now until my app becomes a bit more popular

[mikehardy]

Interesting, I didn't realize that functions wasn't included in the free plan at all. Worth noting that if you go to the blaze plan you get all the free plan stuff, plus for functions the first 2 million calls a month are free. I have a small app and I find myself paying about $2 a month total, and that's only because I do some extensive firestore work for full export / processing. Not saying that would be a good idea for your or not, just to say that it may actually be $0 to upgrade

The biggest fear for me as an app developer is unexpected virality (and a big non-monetized bill...).

You might like item 7 from the "how to cap your firebase costs" official youtube series https://www.youtube.com/playlist?list=PLl-K7zZEsYLmK1tiMBeKA0iDMPDCJKM-5

[lockieluke]

I can't activate the blaze plan cuz I don't have a credit card

[mikehardy]

Definitely a show stopper there 😆 - alright then, doing it on device might be your best option, or using firebase-admin sdk any other spot as you mentioned. Good luck with your project

[lockieluke]

Thanks mate!

[aitmamatovmusa]

In the node js environment, you can delete nested documents and collections via recursiveDelete

import { firestore } from "firebase-admin";

await firestore().recursiveDelete(collectionRef || documentRef);