How do I get the number of subcollectors in Firestore?

Question

I'm making a whiteboard app using Flutter and Firestore. This whiteboard app creates a room first, then creates pages, and then draws inside the page.

Firestore has the following configuration:

I need to be able to get the number of subcollections in Firestore to get the number of pages.

How do I get the number of these subcollections(pages)?

Is room a document and the pages are subcollections of the document? Did I get that right? — PRSHL, Aug 02 '22 at 08:17
Oh, they're both collectors and there's a document in between. I'll fix it. — Kevin Yang, Aug 02 '22 at 08:19

Alex Mamo · Answer 1 · 2022-08-02T17:50:09.743

1

There is no function that can return the number of sub-collections that exist within a document. If you need such a count, you need to create this mechanism yourself. But it's pretty simple, you can create a document in which you can increment/decrement a numeric value, each time a new sub-collection is added or deleted from the document.

edited Aug 02 '22 at 17:50

answered Aug 02 '22 at 09:05

Alex Mamo

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score 1 · Accepted Answer · edited Aug 03 '22 at 17:35

You can't get all collection from one doc in dart.

Retrieving a list of collections is not possible with the mobile/web client libraries. You should only look up collection names as part of administrative tasks in trusted server environments. If you find that you need this capability in the mobile/web client libraries, consider restructuring your data so that subcollection names are predictable.

Here is the document link.

How do I get the number of subcollectors in Firestore?

2 Answers2