Firebase Multipath Fetch Data

Question

Currently, Firebase supports multipath data updates for a flat data layout. However when it comes to fetching data, is it possible to use a similar method to multipath fetch data from multiple locations in Firebase?

For example I need to join some data together and my current code looks like this:

ref.child('data_1/').once('value', function (snapshot) {
    var test_string_1 = snapshot.val();

    ref.child('data_2/').once('value', function (snapshot) {
        var test_string_2 = snapshot.val();

        //...etc 
    });
});

When it comes to having to fetch data from multiple nodes, this nested approach goes quite deep. So I'd like to know if there is a better and faster method, like multipath fetching, to get data from multiple locations.

Answer 1

If the paths/refs are not dependent on each other, you can retrieve them like this:

var test_1 = ref.child('data_1/');
var test_2 = ref.child('data_2/');
Promise.all([
    test_1.once('value'),
    test_2.once('value')
]).then(function(snapshots) {
    var test_string_1 = snapshots[0].val();
    var test_string_2 = snapshots[1].val();
});

See:

• The MDN documentation on Promise.all()
• Speed up fetching posts for my social network app by using query instead of observing a single event repeatedly