// A click to promote a piece on subTurn 2 would trigger this.
// For now it would then return [NaN, NaN] because surrounding squares
// have no IDs in the promotion modal. TODO: improve this?
- if (!square[0]) return null;
+ if (isNaN(square[0])) return null;
// If subTurn == 2:
// if square is empty && firstMove is compatible,
// complete the move (banana or bomb).