javascript - Querying by a field with type 'reference' in Firestore

As you will read here in the doc, the Reference Data Type is used to store DocumentReferences.

If you want to use it in a query, you cannot use a simple string, neither the UID of the document (i.e. '5gF5FqRPvdroRF8isOwd'), nor the string value that is stored in the field (i.e. '/categories/5gF5FqRPvdroRF8isOwd').

You have to build a DocumentReference and use it in your query, as follows:

const categoryDocRef = firebase.firestore()    .collection('categories')    .doc('5gF5FqRPvdroRF8isOwd');  const files = await firebase   .firestore()   .collection('tickets')   .where('category', '==', categoryDocRef)   .get(); 

With Firebase Version 9 (Dec, 2021 Update):

You must make a document reference with "categories/5gF5FqRPvdroRF8isOwdand" then use it in your query:

import { doc, query, collection, where, getDocs } from "firebase/firestore";  const categoryDocRef = doc(db, "5gF5FqRPvdroRF8isOwd");  const q = query(   collection(db, "tickets"),   where("category", "==", categoryDocRef) );  const ticketDocsSnap = await getDocs(q); 

Here is how I use reference type to query a collection (node.js + typescript):

let myCollectionADocument = await admin.firestore().collection("collection_a").doc("documentId").get(); let myCollectionB = await admin.firestore().collection("collection_b").where("collection_a_id", "==", myCollectionADocument.ref).get();