Using a batch to create a collection and a subcollection at once

Question

I'm trying to create a new collection, and then create a sub collection all at once. The code is being run when a user creates a new team and adds a players to the team. (both team and player are created/added at the same time) This is what I have attempted so far:

const batch = db.batch()
const collectionRef = db.collection('users').doc(user.uid).collection('teams').doc(id)

batch.set(
  collectionRef.set({
    teamId: id,
    teamName: teamName
  })
)
batch.set(
  collectionRef.collection('players').doc(player.id).set(playerObject)
)
batch.commit().then(()=> {}).catch(err=> console.log(err))

The player object is defined like so:

{
  name: 'John Doe',
  id: '123',
  imgs: ['img.png']
  ...
}

But whenever this runs, only the first write is executed, the sub collection is not created. I think this is because the collection does not exist, so might cause an issue.

Can you show us the content of `playerObject`? Besides that, how is `collectionRef` defined? — Alex Mamo, Nov 28 '22 at 10:31
I still cannot see where you have defined `const playerObject = ...` — Alex Mamo, Nov 29 '22 at 04:38
The collection will show up in the console when you add a document in it. Do you get any errors in the logs? Have you tried hard coding the document data and ID in the code and see if that works?> — Dharmaraj, Nov 29 '22 at 05:46
@User123123,do let me know if the below recommendations were helpful. — Vaidehi Jamankar, Dec 07 '22 at 06:04

score 0 · Answer 1 · answered Nov 29 '22 at 08:52

Using firestore Batch is a better approach to do this. Create a batch and add the main document followed by the subcollection document(s).A collection is created once a document is written to it, and removed automatically once the last document is removed from it. If you want to write the collection [parent] and the subcollection [child] in a single batch write, you can do it by generating a UniqueID for the parent document, and then creating the sub collection documents under that same path for example as below:

Take a document document under the collection_name collection at the path collection_name/document/
And another one sub-collection_name document under the subCollection_name (sub-)collection
```
collection_name/document/subCollection_name/sub-collection dcoument
```

Also as mentioned above in the comments from Alex,use reference for the collection object while calling the object in the code to create the path for collection and sub-collection reference path, if the reference object and path is not defined the code will not work.

You may check the below examples for similar implementation:

Using a batch to create a collection and a subcollection at once

1 Answers1