Snake on launchpad

snake.js

var midi = require('midi');
 
// Set up a new output.
var output = new midi.output();
var input = new midi.input();
 
output.openPort(0);
input.openPort(0)


const layout = [
    [81, 82, 83, 84, 85, 86, 87, 88, 89],
    [71, 72, 73, 74, 75, 76, 77, 78, 79],
    [61, 62, 63, 64, 65, 66, 67, 68, 69],
    [51, 52, 53, 54, 55, 56, 57, 58, 59],
    [41, 42, 43, 44, 45, 46, 47, 48, 49],
    [31, 32, 33, 34, 35, 36, 37, 38, 39],
    [21, 22, 23, 24, 25, 26, 27, 28, 29],
    [11, 12, 13, 14, 15, 16, 17, 18, 19]
]
	var cw = 1;
	var d;
	var food;
	var score;
    var level;
    var w = 9;
    var h = 8;
	
	var snake_array;
	
	function init()
	{
		d = "none";
		create_snake();
		create_food();
		score = 0;
        level = 1;
		
		if(typeof game_loop != "undefined") clearInterval(game_loop);
		game_loop = setInterval(paint, 150);
	}
	init();
	
	function create_snake()
	{
		var length = 1;
		snake_array = [];
        snake_array.push({x: 4, y:4});
	}
	
	function create_food()
	{
		food = {
			x: Math.round(Math.random()*(w-cw)/cw), 
			y: Math.round(Math.random()*(h-cw)/cw), 
		};
	}
	
	function paint()
	{
		for (let i = 2; i < 90; i++) {
            output.sendMessage([144,i,0]);
        }
        output.sendMessage([144,16,1])
        output.sendMessage([144,27,1])
        output.sendMessage([144,18,1])
        output.sendMessage([144,17,1])
		var nx = snake_array[0].x;
		var ny = snake_array[0].y;
		if(d == "right") nx++;
		else if(d == "left") nx--;
		else if(d == "up") ny--;
        else if(d == "down") ny++;
		
		if(check_collision(nx, ny, snake_array))
		{
			init();
			return;
        }
        
        if (nx == -1) {
            nx = w-1
        } else if (nx == w/cw) {
            nx = 0
        } else if (ny == -1) {
            ny = h-1
        } else if (ny == h/cw) {
            ny = 0
        }
		
		if(nx == food.x && ny == food.y)
		{
			var tail = {x: nx, y: ny};
			score++;
       
			create_food();
		}
		else
		{
			var tail = snake_array.pop();
			tail.x = nx; tail.y = ny;
		}
		
		snake_array.unshift(tail);
		
		for(var i = 0; i < snake_array.length; i++)
		{
			var c = snake_array[i];
			paint_cell(c.x, c.y, 21);
		}
		
		paint_cell(food.x, food.y, 50);
	}
	
	function paint_cell(x, y, color)
	{
		output.sendMessage([144,layout[y][x],color]);
	}
	
	function check_collision(x, y, array)
	{
		for(var i = 0; i < array.length; i++)
		{
			if(array[i].x == x && array[i].y == y)
			 return true;
		}
		return false;
	}
    
    input.on('message', function(deltaTime, message) {
        let key = message[1]
        if(key == "16" && d != "right") d = "left";
        else if(key == "27" && d != "down") d = "up";
        else if(key == "18" && d != "left") d = "right";
        else if(key == "17" && d != "up") d = "down";
      });