code: function getTurnPieces(game) {
      const isBlack = isBlackTurn(game);
      return game.board.reduce((piecesRow, row) => {
          return piecesRow.concat(row.reduce((pieces, position) => (isBlack !== position.isBlack)
              ? pieces
              : pieces.concat({ x: position.x, y: position.y, isBlack }), []));
      }, []);
  }
docs: Gets all positions from current player turn.