Handle issues arrising from objects in data structure by throwing error

src/MUIDataTable.js

@@ -441,14 +441,18 @@ class MUIDataTable extends React.Component {
   };
 
   transformData = (columns, data) => {
-    const leaf = (obj, path) => path.split('.').reduce((value, el) => (value ? value[el] : undefined), obj);
+    const leaf = (obj, path) => path.split('.').reduce((value, el) => {
+      if (typeof value[el] === 'object') throw Error(`Cannot accept objects for cell data from field "${el}". Cells need to contain strings | numbers. It\'s possible this error is the result of a missing dot in the column name field (e.g. name: "company" instead of name: "company.id")`);
+      return value ? value[el] : undefined;
+    }, obj);
 
     return Array.isArray(data[0])
       ? data.map(row => {
           let i = -1;
 
           return columns.map(col => {
             if (!col.empty) i++;
+            if (typeof row[i] === 'object') throw Error(`Cannot accept objects for cell data. Cells need to contain strings | numbers. It\'s possible this error is the result of a missing dot in the column name field (e.g. name: "company" instead of name: "company.id")`);
             return col.empty ? undefined : row[i];
           });
         })