Using a simple update counter to maintain precise ordering of records in Firebase

precise_ordered_records.js

var sequenceRef = new Firebase(...+'/entries');
var updateCounter = new Firebase(...+'/counter');

updateCounter.transaction(function(currentValue) {
    return currentValue+1;
}, function(error, committed, snap) {
    if( error ) { ... }
    else if( committed ) {
       var updateCounter = snap.val();
       sequenceRef.push().setWithPriority({
        updateCounter: updateCounter
        userId: "user123",
        timestamp: Firebase.ServerValue.TIMESTAMP
    }, updateCounter);
});