js-tetris - event listener

main.js

document.addEventListener('keydown', event => {
  if (moves[event.keyCode]) {  
    // Stop the event from bubbling.
    event.preventDefault();
    
    // Get new state of piece
    let p = moves[event.keyCode](board.piece);
    
    if (board.valid(p)) {    
      // If the move is valid, move the piece.
      board.piece.move(p);
      
      // Clear old position before drawing.
      ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height); 
      
      board.piece.draw();
    }
  }
});