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ViewsFetching documents of sub-collections in firestore
I'm trying to fetch sub-collection documents from my firestore database.
Collection Imgs:
My current code:
const fetchHighlight =async()=>{
const Highlight = []
const HighlightDbId = await
db.collection('highlights').doc('2SCS2S0JnzngWEiYkHNk').collection('4C4kd2QnaQhcp9knexkW').get()
console.log(HighlightDbId)
}
React.useEffect(()=>
{
fetchHighlight ()
}, [])
2 answers
Answer question0
You forgot to fetch your query at the end of your chain, and the subcollection 4C4kd2QnaQhcp9knexkW does not exist, it's the id of a document in the subcollection you're trying to access. The right subcollection ID was hBYWvZ3KN3NLLrucTpryETQZnz2.
To sum up, you could go this way:
const yourDocument = (await db.collection('highlights').doc('2SCS2S0JnzngWEiYkHNk')
.collection('hBYWvZ3KN3NLLrucTpryETQZnz2').doc('YOUR_DOC_ID').get()).data()
or this way:
const yourDocument = (await db.collection('highlights/2SCS2S0JnzngWEiYkHNk/hBYWvZ3KN3NLLrucTpryETQZnz2')
.doc('YOUR_DOC_ID').get()).data()
Edit If you want to fetch only the first document of the subcollection you can go this way:
const yourDocument = (await db.collection('highlights').doc('2SCS2S0JnzngWEiYkHNk')
.collection('hBYWvZ3KN3NLLrucTpryETQZnz2') // subcollection ref
.orderBy("createdAt", "asc") // index
.limit(1) // limit the size of your response
.get()) // send the request and wait for it (you could also use '.then()' here)
.docs[0] // get the first doc of the array
.data() // retrieve the doc's data use `.id` instead if you want its id
And if you want to get the first subcollection of a doc you should go this way with the listCollections method:
const subcollectionId = (await db
.doc('highlights/2SCS2S0JnzngWEiYkHNk')
.listCollections())[0] // retrieve the first subcollection `.id`
Note that this only works with the node.js library, if you're attempting to do your query fore the front-end, it will fail. Then you should simply put a reference of your subcollection inside your parent doc by an update when creating your subcollection in the first place:
// const HighlightDbId = creating you subcollection
db.collection('highlights').doc('2SCS2S0JnzngWEiYkHNk').update({
subcollection: HighlightDbId
});
And simply retrieve the field subcollection when you need to fetch data from its subcollection.
0
I fixed this problem by adding the last doc :
db.collection('highlights').doc('2SCS2S0JnzngWEiYkHNk').collection('4C4kd2QnaQhcp9knexkW').doc('XXXXXXXX').get()