@firebase/app-compat

Initialization

This code initializes a Firebase app instance using the older, non-modular syntax. It is used to set up the Firebase context for further interactions with Firebase services.

const firebase = require('@firebase/app-compat');
const app = firebase.initializeApp({ apiKey: 'API_KEY', authDomain: 'PROJECT_ID.firebaseapp.com', projectId: 'PROJECT_ID' });

Authentication

This code demonstrates how to sign in a user with an email and password using Firebase Authentication. It uses the older syntax for ease of use with existing codebases.

const firebase = require('@firebase/app-compat');
const auth = firebase.auth();
auth.signInWithEmailAndPassword('user@example.com', 'password').then((userCredential) => {
  // Handle successful authentication
}).catch((error) => {
  // Handle errors
});

Realtime Database

This code snippet shows how to listen for real-time updates from the Firebase Realtime Database at a specific path. It uses the traditional Firebase syntax.

const firebase = require('@firebase/app-compat');
const database = firebase.database();
database.ref('path/to/data').on('value', (snapshot) => {
  const data = snapshot.val();
  // Use the data
});

Firestore

This code sample demonstrates how to retrieve a document from a Firestore collection using the older Firebase syntax. It is useful for developers who have existing Firestore interactions written in the non-modular style.

const firebase = require('@firebase/app-compat');
const firestore = firebase.firestore();
firestore.collection('users').doc('user_id').get().then((doc) => {
  if (doc.exists) {
    const user = doc.data();
    // Use the user data
  }
}).catch((error) => {
  // Handle errors
});