this.map

function Map() {
	this.move = function(direction) {
		console.log("moving");
	}
}

function Game() {
	this.map = new Map();
	this.handleKeys = function(event) {
		var code = event.keyCode;
		if(code== 38)
      this.map.move("up");
  }
}

var game = new Game();
document.onkeyup = game.handleKeys;