Implementing Batch Write Operations in Firestore with Express

At itselftools.com, our experience in developing over 30 applications utilizing technologies like Next.js and Firebase has offered us profound insights into efficient data handling and server management. One of the common scenarios we frequently handle in our cloud applications is performing bulk data operations, efficiently and securely. In this article, I'll walk you through how to implement a batch write operation in Firestore using an API route in Express.

Code Overview

Take a look at this essential piece of code:

// API Route to perform a batch write operation in Firestore
app.post('/api/batch-write', async (req, res) => {
  const db = firebase.firestore();
  const batch = db.batch();
  const docs = req.body;
  docs.forEach(doc => {
    const docRef = db.collection('items').doc();
    batch.set(docRef, doc);
  });
  await batch.commit();
  res.status(200).send('Batch write successful');
});

Breakdown of the Code

1. Creating an Instance of Firestore: The code starts by creating an instance of Firestore database.

2. Initializing a Batch Operation: We then initialize a batch which is used to accumulate operations that are committed atomically. This helps in reducing network overhead and ensures data integrity during batch processing.

3. Setting Up Document References: Each document from the request body is processed in a forEach loop. For each document, a new document reference is created in the 'items' collection.

4. Writing to the Batch: The document is then added to the batch using batch.set(). Thereby preparing all documents to be written in a single transaction.

5. Committing the Batch: Finally, the batch operations are committed to the database, and upon success, a 200 status message is sent back to the client.

Practical Uses

Batch operations are crucial in scenarios where the application needs to handle large amounts of data simultaneously — for example, when importing data from an external source or when multiple records need to be added or updated at once. This reduces the number of network calls made to the database, thereby enhancing performance and reliability.

Conclusion

Batch writing in Firestore is an essential feature for web applications that require high performance and consistency when handling multiple documents. By using the method described above, developers can enhance their data handling capabilities in Firestore-backed applications.

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