import { Component } from '@angular/core';
import { AngularFireDatabase, AngularFireList } from 'angularfire2/database';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})

export class AppComponent {
  constructor(private af: AngularFireDatabase) {
    const courses$: AngularFireList<any> = af.list('courses');

    courses$.valueChanges().subscribe(val => console.log(val));
  }
}