js-tetris - hard drop

main.js

const KEY = {  
  SPACE: 32,
  // ...
}

moves = {  
  [KEY.SPACE]: p => ({ ...p, y: p.y + 1 })
  // ...
};

// In EventListener
if (event.keyCode === KEY.SPACE) {
  // Hard drop
  while (board.valid(p)) {
    board.piece.move(p);   
    p = moves[KEY.DOWN](board.piece);
  }
}