Cloud Firestore Firebase Database Cheatsheet

Cloud Firestore is a NoSQL, scalable, and serverless cloud database offered by Google Cloud Platform. It’s designed to store and sync data in real-time, making it an excellent choice for building web and mobile applications. This cheatsheet provides a quick reference guide to common operations in Cloud Firestore, along with code snippets to help you get started.

1. Initialize Firestore

To use Cloud Firestore in your application, you need to initialize it first.

// Import the Firestore module
const admin = require('firebase-admin');

// Initialize Firestore
admin.initializeApp();
const db = admin.firestore();

2. Add Data

Adding data to Firestore is straightforward. Use the add method to insert a new document into a collection.

// Add data to a collection
const data = {
  name: 'John Doe',
  age: 25,
  city: 'New York',
};

const docRef = db.collection('users').add(data);
console.log('Document added with ID: ', docRef.id);

3. Read Data

Reading data from Firestore involves querying the database. Use the get method to retrieve documents from a collection.

// Read data from a collection
const usersRef = db.collection('users');
const snapshot = await usersRef.get();

snapshot.forEach((doc) => {
  console.log(doc.id, '=>', doc.data());
});

4. Update Data

Updating data in Firestore can be done using the update method.

// Update data in a document
const docRef = db.collection('users').doc('userID');

// Update the 'age' field to 26
await docRef.update({
  age: 26
});

5. Delete Data

Deleting a document is simple using the delete method.

// Delete a document
const docRef = db.collection('users').doc('userID');
await docRef.delete();

6. Query Data

You can filter and sort data using queries.

// Query data with conditions
const query = usersRef.where('age', '>', 21).orderBy('age', 'desc');
const snapshot = await query.get();

snapshot.forEach((doc) => {
  console.log(doc.id, '=>', doc.data());
});

7. Real-time Updates

Firestore provides real-time updates through snapshots.

// Real-time updates
const docRef = db.collection('users').doc('userID');
docRef.onSnapshot((doc) => {
  console.log('Current data: ', doc.data());
});

8. Batched Writes

Perform multiple write operations as a single batch for atomicity.

// Batched writes
const batch = db.batch();

const docRef1 = db.collection('users').doc('user1');
batch.set(docRef1, { name: 'Alice' });

const docRef2 = db.collection('users').doc('user2');
batch.set(docRef2, { name: 'Bob' });

await batch.commit();

This cheatsheet provides a quick reference for common Cloud Firestore operations. Remember to tailor the code snippets to fit your specific application requirements. For more detailed information, refer to the official Cloud Firestore documentation.

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