JSFiddle - React, Tailwind, and code Playground

by Frank van Puffelen

HTML

<script src="https://cdn.firebase.com/js/client/2.2.7/firebase.js"></script>

JavaScript

var ref = new Firebase('https://nanochat.firebaseio.com');
ref.once('value', function(snapshot) { 
    console.log('all', JSON.stringify(snapshot.val())); 
    var first = ref.orderByKey().limitToFirst(2);
    first.once('value', function(snapshot) {
        console.log("first", snapshot.val());
        var lastKey;
        snapshot.forEach(function(childSnapshot) {
            lastKey = childSnapshot.key();
        });
        var second = ref.orderByKey().startAt(lastKey).limitToFirst(2);
        second.once('value', function(snapshot) {
            console.log("second", snapshot.val());
            var firstKey;
            snapshot.forEach(function(childSnapshot) {
                if (!firstKey) firstKey = childSnapshot.key();
            });
            var back = ref.orderByKey().endAt(firstKey).limitToLast(2);
            back.once('value', function(snapshot) {
                console.log("back", snapshot.val());
            });
        });
    });
})