Feature Request: Official version to delete a collection and all nested documents

[gigocabrera]

Feature Request

Can you include in the Cloud Firestore documentation an official version on how to delete a collection and all nested documents please

For example, if I have the following data structure in Firestore
-- how can I delete a user and all the forms?

users
---userId
-----forms
--------formId

[larssn]

You have to do it manually: loop over every subcollection and delete each document.

[gigocabrera]

Do you have a sample you can share?

[larssn]

Yeah, the official docs have an example: https://firebase.google.com/docs/firestore/manage-data/delete-data

[gigocabrera]

@larssn thank you for the link. However, that is the plain vanilla version of Delete. I was wondering if there is an AngularFirestore version written in Typescript

[larssn]

There's no angularfire version. You'd have to access the native Firestore SDK references:

export class SomeTSClass {
  constructor(private db: AngularFirestore) {}

  async deleteCol(path) {
    const qry: firebase.firestore.QuerySnapshot = await this.db.collection(path).ref.get();

    // You can use the QuerySnapshot above like in the example i linked
    qry.forEach(doc => {
      doc.ref.delete();
    });
  }
}

The above example is off the top of my head, so it might contain errors, but the principle is there.

[gigocabrera]

@larssn you're awesome!!! Thank you very much. I'll give it a try and update this ticket with findings

[davideast]

Hi @gigocabrera! I would love this feature as well. However, AngularFire is a wrapper around the core SDK. Route any future feature requests to the official SDK repo. They are much wiser than me :)

[gigocabrera]

Thank you @davideast 🍺

[kctang]

Hi all,

Sharing a function to delete all documents in named collections, by batches. It returns a promise with total number of deleted documents. It does not delete subcollections. Internally, uses rxjs to do the magic of streaming and batching values to be deleted.

  /**
   * Delete all documents in specified collections.
   *
   * @param {string} collections Collection names
   * @return {Promise<number>} Total number of documents deleted (from all collections)
   */
  async deleteCollections (...collections: string[]) {
    let totalDeleteCount = 0
    const batchSize = 500
    return new Promise<number>((resolve, reject) => Observable
      .from(collections)
      .concatMap(collection => Observable.fromPromise(this.fireStore.collection(collection).ref.get()))
      .concatMap(q => Observable.from(q.docs))
      .bufferCount(batchSize)
      .concatMap((docs: QueryDocumentSnapshot[]) => Observable.create((o: Observer<number>) => {
          const batch = this.fireStore.firestore.batch()
          docs.forEach(doc => batch.delete(doc.ref))
          batch.commit()
            .then(() => {
              o.next(docs.length)
              o.complete()
            })
            .catch(e => o.error(e))
        })
      )
      .subscribe(
        (batchDeleteCount: number) => totalDeleteCount += batchDeleteCount,
        e => reject(e),
        () => resolve(totalDeleteCount)
      )
    )
  }

[gigocabrera]

@kctang that's awesome, thank you! I'll give it a try this weekend

[tgangso]

Thanks @kctang works like a charm.

[louisptremblay]

here's the function from the docs (node.js but works as is in javascript if you replace process.nextTick by setTimeout 0)
https://github.com/firebase/snippets-node/blob/a2a7b6763c5bfd3b7eb833742086cb3b74a71375/firestore/main/index.js#L801-L840

[adam-hurwitz]

I used this as a workaround to delete a user's Collection from the Android client. Passed into the method is the reference of the user's Collection and the batch size to process. I will refactor this onto the server as recommended by the documentation, but am using this for my proof of concept in the meantime.

    fun deleteCollection(collection: CollectionReference, batchSize: Int) {
        try {
            // Retrieve a small batch of documents to avoid out-of-memory errors/
            var deleted = 0
            collection
                    .limit(batchSize.toLong())
                    .get()
                    .addOnCompleteListener {
                        for (document in it.result.documents) {
                            document.getReference().delete()
                            ++deleted
                        }
                        if (deleted >= batchSize) {
                            // retrieve and delete another batch
                            deleteCollection(collection, batchSize)
                        }
                    }
        } catch (e: Exception) {
            System.err.println("Error deleting collection : " + e.message)
        }
    }

[swftvsn]

The solution here can be easily adapted for frontend too: firebase/firebase-admin-node#361