Solution for http://play.elevatorsaga.com/ levels 1-6

gistfile1.js

{
    init: function(elevators, floors) {
        var waitingFloors = [];
        _.each(elevators, function(elevator) {
            elevator.on("floor_button_pressed", function(floorNum) {
                 elevator.goToFloor(floorNum);
            }); 
            elevator.on("up_button_pressed", function(floorNum) {
                 elevator.goToFloor(floorNum);
            });
            elevator.on("idle", function() {
                var waiting = waitingFloors[0];
                if (waiting) {
                    elevator.goToFloor(waiting.level);
                } else {
                    elevator.goToFloor(0);   
                }
            });
            elevator.on("stopped_at_floor", function(floorNum) {
                var floor = floors[floorNum];
                var index = waitingFloors.indexOf(floor);
                if (index) {
                    waitingFloors.splice(index, 1);
                }
            });
        });
        _.each(floors, function(floor) {
            floor.on("up_button_pressed down_button_pressed", function() {
                waitingFloors.push(floor);
            });
        });
        
    },
    update: function(dt, elevators, floors) {
        // We normally don't need to do anything here
    }
}