Alright, let's get started with batch writes in Firebase Firestore. First things first, we need to initialize Firebase in our project. This means setting up Firebase and Firestore in your app.

import { initializeApp } from "firebase/app";
import { getFirestore } from "firebase/firestore";

const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_AUTH_DOMAIN",
  projectId: "YOUR_PROJECT_ID",
  storageBucket: "YOUR_STORAGE_BUCKET",
  messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
  appId: "YOUR_APP_ID"
};

// Initialize Firebase
const app = initializeApp(firebaseConfig);

// Initialize Firestore
const db = getFirestore(app);

Next up, let's create a new batch instance using the batch() method. This is where the magic happens.

import { writeBatch } from "firebase/firestore";

const batch = writeBatch(db);

Now, let's set up our batched writes. You can use the set, update, or delete methods on the batch instance to perform multiple operations in one go.

import { doc, setDoc, deleteDoc, updateDoc } from "firebase/firestore";

// Document reference
const docRef1 = doc(db, "collectionName", "doc1");
const docRef2 = doc(db, "collectionName", "doc2");
const docRef3 = doc(db, "collectionName", "doc3");

// Set data for the document
batch.set(docRef1, { field1: "value1", field2: "value2" });

// Update data for the document
batch.update(docRef2, { field1: "newValue1" });

// Delete the document
batch.delete(docRef3);

Once you've added all your operations to the batch, it's time to commit the batch. This will execute all the operations at once.

batch.commit().then(() => {
  console.log("Batch write successfully committed!");
}).catch((error) => {
  console.error("Error committing batch write: ", error);
});

Finally, let's add some error handling to make sure everything goes smoothly. This will help you catch any issues that might pop up.

try {
  await batch.commit();
  console.log("Batch write successfully committed!");
} catch (error) {
  console.error("Error committing batch write: ", error);
}

Just a heads-up: Firestore limits each batch to 500 writes, so make sure you don't go over this limit to avoid any hiccups.