Задача про лифт

vasiliy_elevator.js

var DIRECTION_DOWN = -1
var DIRECTION_NONE = 0
var DIRECTION_UP = 1

function HardwareElevator(){};
HardwareElevator.prototype = {
    moveUp:function(){console.log('moving up');},
    moveDown:function(){console.log('moving down');},
    stopAndOpenDoors:function(){console.log('stopping and opening doors');},
    getCurrentFloor:function(){console.log('getting current floor');},
    getCurrentDirection:function(){console.log('getting current drection');}
}

function Elevator() {
    this.hw = new HardwareElevator();
    this.hw.addEventListener("doorsClosed", _bind(this.onDoorsClosed, this));
    this.hw.addEventListener("beforeFloor", _bind(this.onBeforeFloor, this));
    
    this.queue = []; // list of tasks
}
Elevator.prototype = {
    onDoorsClosed: function(floor) {
        this._nextMovement();
    },
    onBeforeFloor: function(floor, direction) {
        this._prevDirection = direction;
        if(var task = this.queue.find(item => item.floor === floor && item.direction === direction)) {
            this.queue = this.queue.filter(i => i === task);
            this.stopAndOpenDoors();
        }else if(!this.queue.find(item => isNext(item.floor, floor, direction)) {
            this.queue = this.queue.filter(i => i.floor !== floor);
            this.stopAndOpenDoors();
        }
    },
    floorButtonPressed: function(floor, direction) {
        this.queue.push({floor, direction});
        (this.queue.length === 1) && this._nextMovement();
    },
    cabinButtonPressed: function(floor) {
        // if currentFloor not equ to floor - add request to queue
        direction = floor - this.getCurrentFloor(); // ??
        direction /= Math.abs(direction);
        direction && this.queue.push({floor, direction});
        // { floor, direction } === { floor: floor, direction: direction };
        (this.queue.length === 1) && this. _nextMovement();
    },
    _nextMovement() {
        var currentFloor = this.getCurrentFloor();
        var direction = this._prevDirection  || this.getCurrentDirection();
        if(!this.queue.length) {
            return;
        }
        var targetFloor;
        if(direction === DIRECTION_UP) {
            targetFloor = Math.max(...this.queue.map(i => i.floor));
        } else if(direction === DIRECTION_DOWN) {
            targetFloor = Math.min(...this.queue.map(i => i.floor));
        } else {
            targetFloor = this.queue[0].floor;
        }
        
        var taskDirection = targetFloor - currentFloor;
        taskDirection /= Math.abs(taskDirection);
        var movement = taskDirection === DIRECTION_DOWN ? 'modeDown' : 'moveUp';
        taskDirection && this.hw[movement]();
    }
}

function isNext(floor, currentFloor, direction) {
    if(direction === DIRECTION_UP) {
        return floor > currentFloor;
    } else if (direction === DIRECTION_DOWN) {
        return floor < currentFloor;
    }
    return floor !== currentFloor;
}