Ensure that only the visible columns are exported.

src/dash-table/components/Export/index.tsx

@@ -1,6 +1,6 @@
 import XLSX from 'xlsx';
 import React from 'react';
-import { IDerivedData, Columns, ExportHeaders, ExportFormat, ExportColumns } from 'dash-table/components/Table/props';
+import { IDerivedData, Columns, Data, Datum, ExportHeaders, ExportFormat, ExportColumns } from 'dash-table/components/Table/props';
 import { createWorkbook, createHeadings, createWorksheet } from './utils';
 import getHeaderRows from 'dash-table/derived/header/headerRows';
 
@@ -14,6 +14,21 @@ interface IExportButtonProps {
     merge_duplicate_headers: boolean;
 }
 
+export function filterData(data: Data, columnID: string[]) {
+
+    let filteredData: Data = [];
+
+    data.forEach(data_row => {
+        let filtered_row: Datum = {};
+        columnID.forEach(column => {
+            filtered_row[column] = data_row[column];
+        });
+        filteredData.push(filtered_row);
+    });
+
+    return filteredData;
+}
+
 export default React.memo((props: IExportButtonProps) => {
 
     const { columns, export_columns, export_format, virtual_data, export_headers, visibleColumns, merge_duplicate_headers } = props;
@@ -27,12 +42,12 @@ export default React.memo((props: IExportButtonProps) => {
 
         const maxLength = getHeaderRows(columns);
         const heading = (export_headers !== ExportHeaders.None) ? createHeadings(columnHeaders, maxLength) : [];
-        const ws = createWorksheet(heading, virtual_data.data, columnID, export_headers, merge_duplicate_headers);
+        const ws = createWorksheet(heading, filterData(virtual_data.data, columnID), columnID, export_headers, merge_duplicate_headers);
         const wb = createWorkbook(ws);
         if (export_format === ExportFormat.Xlsx) {
-            XLSX.writeFile(wb, 'Data.xlsx', {bookType: 'xlsx', type: 'buffer'});
+            XLSX.writeFile(wb, 'Data.xlsx', { bookType: 'xlsx', type: 'buffer' });
         } else if (export_format === ExportFormat.Csv) {
-            XLSX.writeFile(wb, 'Data.csv', {bookType: 'csv', type: 'buffer'});
+            XLSX.writeFile(wb, 'Data.csv', { bookType: 'csv', type: 'buffer' });
         }
     };