What are some examples of Firestore transactions?

What are some examples of Firestore transactions?

Firestore transactions allow you to perform multiple read and write operations atomically. For example, you can update a user's balance and log the transaction in one go.

Can you show me a code example of a Firestore transaction?

Sure! Here's a simple example in JavaScript:

const db = firebase.firestore();
const userRef = db.collection('users').doc('user_id');
const transactionRef = db.collection('transactions').doc();

await db.runTransaction(async (transaction) => {
  const userDoc = await transaction.get(userRef);
  const newBalance = userDoc.data().balance - 100;
  transaction.update(userRef, { balance: newBalance });
  transaction.set(transactionRef, { amount: 100, type: 'debit' });
});

What happens if one of the operations fails?

If any operation in a Firestore transaction fails, all operations are rolled back, ensuring data consistency.

Are there any limitations to Firestore transactions?

Yes, Firestore transactions can only read and write to a maximum of 500 documents at a time.