Adding data to nested collection firebase cloud firestore

Question

Right now my firebase cloud firestore looks like this: const db = fire.firestore(); db.collection("groupFavs/"+groupID+ "/"+currentUserUID).add({favs: likedData}) The code above creates a collection called groupFavs, a document called groupID and another collection with the current users id. In the image I have above, it keeps creating documents for the users likes when i just want the currentuser id to only have one list in it which will be all their liked data. But instead it just keeps making multiple of them and I think its because of .add I've tried using set but that wont work. Where am I going wrong? db.collection("groupFavs2") .doc(groupID).collection(currentUserUID) .set({ favs: likedData }) I basically want to do something like this above but my logic is off in regards to the nested collection because what im calling above does not work JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

You can circumvent the string concatenation as well as the nested .collection .doc chain by using string interpolation as follows: const collectionRef = db.collection(`groupFavs/${groupID}/${currentUserUID}`) collectionRef.add({favs: likedData}) In regards to the multiple documents, you are adding a new document under the sub collection (matching the users id). Ideally this would look something like this: Group Favs 1st UserId Like 1 doc Like 2 doc 2st UserId Like 1 doc Like 2 doc Where the like doc can contain information related to the like such as image or liked boolean property. If instead what you would like to do is keep a list of the users likes under their doc you can do it as follows: const docRef= db.doc(`groupFavs/${groupID}/${currentUserUID}`) const newLikeData = { likes: firestore.FieldValue.arrayUnion() } docRef.set({favs: likedData}, {merge:true}) arrayUnion will append whatever data is in . Alternatively, you could query for the current likes list under the users doc, manually append the information and pass the entire object to a update or setDoc with merge: true.