import { firestore } from 'firebase/app';
import Timestamp = firestore.Timestamp;
@Injectable()
export class YourService {
....
list = (): Observable<any[]> => this.collection
.snapshotChanges()
.pipe(
map(changes => {
return changes.map(a => {
const data = a.payload.doc.data() as any;
Object.keys(data).filter(key => data[key] instanceof Timestamp)
.forEach(key => data[key] = data[key].toDate())
data._id = a.payload.doc.id;
return data;
});
})
);
...
}