Merge Firestore streams using rxDart

问题:

I am trying to merge two streams from Firestore into one stream using RxDart, but it's only returning results of one stream

Stream getData() {
    Stream stream1 = Firestore.instance.collection('test').where('type', isEqualTo: 'type1').snapshots();
    Stream stream2 = Firestore.instance.collection('test').where('type', isEqualTo: 'type2').snapshots();
    return Observable.merge(([stream2, stream1]));
}

回答1:

Depending on your use case, you might not need RxDart to do this. If you just want to have two Firestore streams merged to one Dart Stream you can use StreamZip from the dart:async package.

import 'dart:async';     

Stream<List<QuerySnapshot>> getData() {
  Stream stream1 = Firestore.instance.collection('test').where('type', isEqualTo: 'type1').snapshots();
  Stream stream2 = Firestore.instance.collection('test').where('type', isEqualTo: 'type2').snapshots();
  return StreamZip([stream1, stream2]).asBroadcastStream();
}