http://play.elevatorsaga.com/

elevatorsaga.js

{
    init: (elevators, floors) => {
        const max = array => Math.max.apply(null, array);
        const min = array => Math.min.apply(null, array);
        const asc = (a, b) => a - b;
        const desc = (a, b) => b - a;
        const upPressedFloors = [];
        const downPressedFloors = [];
        const sortElevatorQueue = elevator => {
            elevator.destinationQueue.sort(elevator.destinationDirection === 'up' ? asc : desc);
            elevator.checkDestinationQueue();
        };
        elevators.forEach(elevator => {
            elevator.on('floor_button_pressed', (floorNum) => {
                elevator.goToFloor(floorNum);
                sortElevatorQueue(elevator);
            });
            elevator.on("passing_floor", (floorNum, direction) => {
                if (elevator.loadFactor() >= 0.9) return;
                if (upPressedFloors.find(f => f === floorNum) && direction === 'up') {
                    upPressedFloors.splice(upPressedFloors.indexOf(floorNum), 1);
                    elevator.goToFloor(floorNum, true);
                }
                if (downPressedFloors.find(f => f === floorNum) && direction === 'down') {
                    downPressedFloors.splice(downPressedFloors.indexOf(floorNum), 1);
                    elevator.goToFloor(floorNum, true);
                }
            });
            elevator.on('stopped_at_floor', floorNum => {
                // TODO indicate going up or down
            });
            elevator.on("idle", () => {
                elevator.goToFloor(
                    [elevator.currentFloor(), min(upPressedFloors), max(downPressedFloors)]
                    .filter(f => f != -Infinity)
                    .sort((a, b) => Math.abs(b - elevator.currentFloor()) - Math.abs(a - elevator.currentFloor()))
                    .indexOf(0)
                );
            });
        });
        floors.forEach(floor => {
            const floorNum = floor.floorNum();
            floor.on('up_button_pressed', () => {
                upPressedFloors.push(floorNum);
            });
            floor.on('down_button_pressed', () => {
                downPressedFloors.push(floorNum);
            });
        });
    },
    update: (dt, elevators, floors) => {}
}