add check

Author: spencergray96

package.json

@@ -1,6 +1,6 @@
 {
   "name": "frame-one-table",
-  "version": "0.3.11",
+  "version": "0.3.12",
   "description": "A react table with maximum flexibility.",
   "main": "build/index.js",
   "module": "build/index.es.js",

src/TableRow.tsx

@@ -59,7 +59,7 @@ const TableRow: React.FC<ITableRowProps> = (props) => {
 		// Generate classes for the header cell.
 		const _rowClassName: string = (typeof column.rowCellClassName === "string" || !column.rowCellClassName) ?
 			column.rowCellClassName as string :
-			column.rowCellClassName(content.toString(), cellContextDetails);
+			column.rowCellClassName(content?.toString(), cellContextDetails);
 		const cellClasses: string = classNames(rowCellClassName, _rowClassName);
 
 		return (