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Firebase v9 ,Cannot get document from a nested collection

I feel like it was easier to get subcollection in v8 ,It’s been like 2 days trying to do it the new way but I gave up.

Im building a simple react social media app for learning purposes. where each user logs in and be able to post some text (and images but not atm), I have a main collection for Users and it has the users ID .each of these users have a collection called Posts and it contains all the user posts.

here i want to access the Post collection for each user and then access the posts

I can do so by entering the UID of each user like so

but I can only access the current user id

so what can i do to access the Users collection then get ALL the users and be able to access the Posts subcollection?

ps : sorry if any part of this question is unclear ,english isn’t my first language and it’s my first time posting here. appreciate any help!.

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Answer

If you want to fetch posts from all the users, you are looking for collectionGroup queries using which you can fetch documents in all the sub-collections named as ‘posts’. You can run a collectionGroup query using Modular SDK (V9) as shown below:

import { getFirestore, getDocs, collectionGroup } from "firebase/firestore"
const db = getFirestore()

const allPosts = await getDocs(collectionGroup(db, "posts"))
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