elevator_saga.js

{
    init: function(elevators, floors) {
        let tasks = [];

        for (let index in floors) {
            let floor = floors[index];
            floor.on("up_button_pressed", () => {
                tasks.push({
                    floor: floor.floorNum(),
                    dir: "up",
                });
            });
            floor.on("down_button_pressed", () => {
                tasks.push({
                    floor: floor.floorNum(),
                    dir: "down",
                });
            })
        }

        for (let index in elevators) {
            let elevator = elevators[index];
            elevator.dir = "up";

            elevator.pickup = function() {
                if (tasks.length === 0) {
                    return;
                }

                elevator.goToFloor(tasks[0].floor);
                tasks.splice(0, 1);
            };

            elevator.on("idle", function() {
                if (elevator.getPressedFloors().length == 0) {
                    elevator.pickup();
                    return;
                }

                if (elevator.dir == "up") {
                    let next = 9999;
                    for (let floor of elevator.getPressedFloors()) {
                        if (floor < elevator.currentFloor()) {
                            continue;
                        }

                        next = Math.min(next, floor);
                    }

                    elevator.goToFloor(next);
                    return;
                } else {
                    let next = -1;
                    for (let floor of elevator.getPressedFloors()) {
                        if (floor > elevator.currentFloor()) {
                            continue;
                        }

                        next = Math.max(next, floor);
                    }

                    elevator.goToFloor(next);
                    return;
                }
            });
        }
    },
        update: function(dt, elevators, floors) {
            // We normally don't need to do anything here
        }
}

Stuck at challenge 12