Firestore: What's the Pattern for Adding New Data in Web V9

Firestore: What's the pattern for adding new data in Web v9?

If you are trying to get:

• a CollectionReference, then use collection():

const myCol = collection(db, "collection", "doc1", "sub-col1")

• a DocumentReference, then use doc():

const myDoc = doc(db, "collection", "doc1", "sub-col1", "sub-doc1")

The concept remains same. The path to a document has even number of segments e.g. col/doc/sub-col/sub-doc while path to a collection has odd e.g. col/doc/sub-col.

Both the methods will throw an error if invalid number of parameters are passed.

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In the name-spaced version (v8), it used to look like:

// DocumentReference
firebase.firestore().doc("col/doc/sub-col/sub-doc")

// CollectionReference
firebase.firestore().collection("col/doc/sub-col")

In essence, you keep adding path segments to the same doc() or collection() methods.

doc(firestore: Firestore, path: string, ...pathSegments: string[]):
// You can also use spread operator with an array

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An example with spread operator:

const myDocPath = "users/user1/posts/post1/comments/comment1"
const docRef = doc(db, ...myDocPath.split("/"))

Just make sure you don't have any leading or trailing slash if using spread operator with split().

Firebase 9 - How to do new doc ref

The doc() method is equivalent to .collection('users').doc('docID') where you need to specify the ID. If you are trying to add a document with random ID then you add use addDoc() with collection() as shown below:

const usersCol = collection(db, 'Users')

await addDoc(usersCol, {...data})

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If you want the random ID before adding the document then you can try this:

const userRef = doc(collection(db, 'Users'));
console.log(userRef.id)

Document references must have an even number of segments, but Users has 1.

You can checkout this answer for explanation of doc() and collection():

Firestore: What's the pattern for adding new data in Web v9?

How to create a custom id document in firestore(Firebase modular SDK (v9))

You can use setDoc() method to specify an ID instead of addDoc which will generates a random ID as mentioned in the documentation:

const adminRef = doc(firestore, 'admin', collegeId);
//       doc  --->^
await setDoc(adminRef, {email: adminEmail, id: collegeId}) // overwrites the doc if it already exists
//    ^^^

Also note that to create a DocumentReference you need to use doc() and not collection() which is used to create a CollectionReference. I've explained difference in these 2 here: Firestore: What's the pattern for adding new data in Web v9?

How do you create a new Firestore document within a transaction

If you are specifying the document ID (and not using the auto-generated IDs) then you must use doc() instead of collection() to create a DocumentReference:

const newLogRef = doc(db, 'transactionLogs', transactionLog.timeStamp);

The collection() function is used create a CollectionReference.

Also checkout: Firestore: What's the pattern for adding new data in Web v9?

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My understanding is that transaction.set will create a new record if the supplied reference doesn't exist

If the documents exists, the it'll overwrite the existing document.

Fetch Single Data by Document Id Reactjs Firebase Web SDK 9

You can use getDoc() function to fetch a single document as shown below:

import { doc, getDoc } from "firebase/firestore";

useEffect(() => {
  const fetchDocById = async () => {
    // Create DocumentReference
    const docRef = doc(db, "reports", id) // db = getFirestore()
    
    // Fetch document
    const docSnap = await getDoc(docRef)
    
    if (snapshot.exists()) {
      setUser({
        ...snapshot.val()
      });
    } else {
      setUser({});
    }
  }

  fetchDocById()
}, [id]);

Also checkout: Firestore: What's the pattern for adding new data in Web v9?

Firebase - How can i get data from reference?

If you have the DocumentReference already then you can use getDoc() function to retrieve the document from Firestore as shown below:

import { getDoc, DocumentReference } from "firebase/firestore";

export const getClubById = async (clubDocRef: DocumentReference) => {
  const clubSnapshot = await getDoc(clubDocRef);
  return clubSnapshot.data();
}

// Pass the reference itself to the function instead of doc ID
const club = await getClubById(userData.selectedClub)

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For the error in the question, to create a DocumentReference, if you have the document ID then you should doc() function instead of collection() that is used to create a CollectionReferencce as shown below:

const docRef = doc(db, 'clubs', clubID);

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Also checkout: Firestore: What's the pattern for adding new data in Web v9?

Firebase new namespace for .where() .limit() .orderBy()

Almost every Firebase method is a top-level function in Modular SDK and can be imported directly from the relevant SDKs. Try refactoring the code as shown below.

import { collection, getDocs, query, where, limit, orderBy } from "firebase/firestore";

const getDB = async () => {
  const colRef = collection(db, "collection");

  // Keep adding query clauses in query()
  // like chaining them in name-spaced V8 version
  const q = query(colRef, where("field", "==", "value"), limit(1));

  const data = await getDocs(q);
  console.log(data.docs.map((doc) => ({ ...doc.data(), id: doc.id })))
}

The name-spaced version of the same query for reference:

const q = db.collection("col").where("field", "==", "value").limit(1);

You can find list of all functions in the new Firestore SDK in the documentation.

Also checkout:

• Order and limit data with Cloud Firestore (Refer to Modular tab in Documentation)
• Perform simple and compound queries in Cloud Firestore
• Firestore: What's the pattern for adding new data in Web v9?
• Firestore conditional where clause using Modular SDK v9

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