Angular Fire

AngularFire is the official library that connects Angular to Firebase. AngularFire provides real-time updates through observable streams and is highly optimized. Under the hood, AngularFire is also using a custom protocol called “WebChannel” which operates to create real-time synchronization.
Features:

Observable based
Real-time bindings
Authentication
Offline Data
Server-side Render
ngrx friendly
Call server code
Push notifications