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Create a simple Messageboard with Firebase and Angular4

Von


You want that your users can leave messages in your Angular Application. In this Article I explain how you can implement this with Angular 4 and Firebase.


First we have to import the Moduls for Firebase in our app.module.ts and our component.

app.module.ts
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule, AngularFireDatabase, FirebaseListObservable } from 'angularfire2/database';



@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    AngularFireModule.initializeApp(firebaseConfig),
    AngularFireDatabaseModule,

We also have to configure the AngularFireModule.


export const firebaseConfig = {
  apiKey: "",
    authDomain: "",
    databaseURL: "",
    projectId: "",
    storageBucket: "",
    messagingSenderId: ""
};

You get this information at your Firebase console.





component:

import { AngularFireDatabaseModule, AngularFireDatabase, FirebaseListObservable } from 'angularfire2/database';
import * as firebase from 'firebase/app';



Then we declare a variable in which we save the input and this variable get pushed to Firebase. These item variable is from type FireBaseListObservable We also need a message variable.


items: FirebaseListObservable<any[]>
message: any

Now we write our function. In my case I push a message and the name from the user to the Firebase Database. I am getting the name from the social login. You can read in my previous article, how you can set up the social login in your Angular application.


chatSend(theirMessage: string) {
      this.items.push({ message: theirMessage, name: this.afAuth.auth.currentUser.displayName});
      this.message = "";
  }

If we done this it’s time to write some HTML. 

<div  *ngIf="(user | async)?.uid">
<input type="text" id="message"  placeholder="Chat here..." (keyup.enter)="chatSend($event.target.value)" [(ngModel)]="message" >

    <div *ngFor="let item of items | async">
      <a href="#">{{item.name}}</a>
      
      <p>{{item.message}}</p>
    </div> 
</div>

I don’t show the message board if the user is not logged in. 

*ngIf="(user | async)?.uid"

If the user is logged in, the user can write a message and send it via enter. I am using keyup.enter to call our chatSend function.
<input type="text" id="message"  placeholder="Chat here..." (keyup.enter)="chatSend($event.target.value)" [(ngModel)]="message" >

Below our input line I show all messages with the users displayname. Don’t forget using async, when you are working with Firebase.


<div *ngFor="let item of items | async">
      <a href="#">{{item.name}}</a>    
      <p>{{item.message}}</p>
    </div> 



That’s it!


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