import 'rxjs/add/operator/map'; using AngularFirestore, AngularFirestoreCollection, AngularFirestoreDocument

Question

constructor(public afs: AngularFirestore) { this.itemsCollection = this.afs.collection('items', ref => ref.orderBy('title', 'asc'));

this.items = this.itemsCollection.snapshotChanges().map(changes => {
  return changes.map(a => {
    const data = a.payload.doc.data() as Item;
    data.id = a.payload.doc.id;
    return data;
  });
});

} map is not recognized.

Answer 1

You need to use pipe to add operators on the observable flow, try:

this.items = this.itemsCollection.snapshotChanges().pipe(map(changes => {
  return changes.map(a => {
    const data = a.payload.doc.data() as Item;
    data.id = a.payload.doc.id;
    return data;
  });
}));