Function observe

examples/00 Chessboard/Tutorial App/Game.js:8–19

(o)

}

export function observe(o) {
  if (observer) {
    throw new Error('Multiple observers not implemented.');
  }

  observer = o;
  emitChange();

  return () => {
    observer = null;
  };
}

export function canMoveKnight(toX, toY) {
  const [x, y] = knightPosition;