keys.js

;(function() {

    'use strict';

    var t;

    function KeyListener(grid,timer) {

        t=this;

        t.grid=grid;

        t.timer=grid.timer;

        t.inititialiseKeys();

    }

    KeyListener.prototype = {  

        // the grid the events happen to
        grid:{},     

        // the timer triggering intervals
        timer:{}, 

        /**
         * inititialiseKeys() - adds an event listener for keypresses
         */
        inititialiseKeys:function()
        {

            window.addEventListener('keydown',t.keyListener);

        },

        /**
         * keyListener() - responds to the key presses for game play
         */
        keyListener:function(keyEvent)
        {
            
            var cells=t.grid.cells;

            var inPlayPiece=t.grid.pieces[1];

            switch (keyEvent.keyCode)
            {

                case 37:                  
                    keyEvent.preventDefault();
                    inPlayPiece.movePiece(cells,'left',t.timer);
                    break;
                case 39:
                    keyEvent.preventDefault();
                    inPlayPiece.movePiece(cells,'right',t.timer);
                    break;
                case 40:
                    keyEvent.preventDefault();
                    inPlayPiece.movePiece(cells,'down',t.timer);
                    break;

                case 32:
                    keyEvent.preventDefault();
                    inPlayPiece.rotate(cells);
                    break;

                case 49: // 1 key for pausing
                    keyEvent.preventDefault();
                    if (true === t.timer.running)
                    {
                        t.timer.pauseTimer();
                    }
                    else
                    {
                        t.timer.startTimer();
                    }
                    break;


            }

        }

    };

    window.KeyListener = KeyListener;

}());