code: function getBoardWithPieces(board, pieces) {
      return mapBoard(board, function (p) {
          var x = p.x,
              y = p.y;
  
          var piece = Position.getPositionFromPositions(pieces, p);
          return piece ? { x: x, y: y, isBlack: piece.isBlack } : { x: x, y: y };
      });
  }
docs: Takes a board and return a new board with pieces.