Update version-4-upgrade.md

[ashishpatelcs]

Upgrading to AngularFire2 4.0

AngularFire2 4.0 is a refactor of the AngularFire2 package which implements
@NgModule, simplifies authentication, and better supports Angular 4.

Removing AngularFire for Modularity

Prior to 4.0, AngularFire2 did not take advantage of the Firebase SDK's modularity for tree shaking. The AngularFire service has now been removed and the library is broken up into smaller @NgModules:

• AngularFireModule
• AngularFireDatabaseModule
• AngularFireAuthModule

When upgrading, replace calls to AngularFire.database and AngularFire.auth with AngularFireDatabase and AngularFireAuth respectively.

constructor(af: AngularFire) {
  af.database.list('foo');
  af.auth;
}

Should now be:

constructor(db: AngularFireDatabase, afAuth: AngularFireAuth) {
  db.list('foo');
  afAuth.authState;
}

Simplified Authentication API

In 4.0 we've reduced the complexity of the auth module by providing only firebase.User observers (AngularFireAuth.authState, AngularFireAuth.idToken) and cutting the methods that were wrapping the Firebase SDK.

import { AngularFireAuth } from 'angularfire2/auth';
// Do not import from 'firebase' as you'd lose the tree shaking benefits
import firebase from 'firebase/app';
...

user: Observable<firebase.User>;
constructor(afAuth: AngularFireAuth) {
  this.user = afAuth.authState; // only triggered on sign-in/out (for old behavior use .idToken)
}

AngularFire2 exposes the raw Firebase Auth object via AngularFireAuth.auth. For actions like login, logout, user creation, etc. you should use the methods available to firebase.auth.Auth.

While convenient, the pre-configured login feature added unneeded complexity. AngularFireModule.initializeApp no longer takes a default sign in method. Sign in should be done with the Firebase SDK via firebase.auth.Auth:

login() {
  this.afAuth.auth.signInWithPopup(new firebase.auth.GoogleAuthProvider());
}
logout() {
  this.afAuth.auth.signOut();
}

FirebaseListFactory and FirebaseObjectFactory API Changes

If you directly use FirebaseListFactory or FirebaseObjectFactory you will no longer be able to pass in a string, it will instead expect a Firebase database reference.

Putting this all together

Here's an example of what AngularFire2 4.0 looks like:

import { NgModule, Component } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule, AngularFireDatabase, FirebaseListObservable } from 'angularfire2/database';
import { AngularFireAuthModule, AngularFireAuth } from 'angularfire2/auth';
import { environment } from '../environments/environment';

// Do not import from 'firebase' as you'd lose the tree shaking benefits
import firebase from 'firebase/app';


@NgModule({
  declarations: [ App ],
  exports: [ App ],
  imports: [ 
    AngularFireModule.initializeApp(environment.firebase, 'my-app'),
    AngularFireDatabaseModule,
    AngularFireAuthModule
  ],
  bootstrap: [ App ]
})
export class MyModule { }

@Component({
  selector: 'my-app',
  template: `
    <div> {{ (items | async)? | json }} </div>
    <div> {{ (user | async)? | json }} </div>
    <button (click)="login()">Login</button>
    <button (click)="logout()">Logout</button>
  `
})
export class App {
  user: Observable<firebase.User>;
  items: FirebaseListObservable<any[]>;
  constructor(afAuth: AngularFireAuth, db: AngularFireDatabase) {
    this.user = afAuth.authState;
    this.items = db.list('items');
  }
  login() {
    this.afAuth.auth.signInWithPopup(new firebase.auth.GoogleAuthProvider());
  }
  logout() {
     this.afAuth.auth.signOut();
  }
}

Checklist

• Issue number for this PR: #nnn (required)
• Docs included?: (yes/no; required for all API/functional changes)
• Test units included?: (yes/no; required)
• In a clean directory, yarn install, yarn test run successfully? (yes/no; required)

Description

Code sample