New: autoFilter option for -button excelHtml5 which can be used to enable Excel's AutoFilter option on the table headers in the exported spreadsheet.

- https://datatables.net/forums/discussion/comment/130547

Author: AllanJard

docs/button/excelHtml5.xml

@@ -234,6 +234,11 @@
 		Message to be shown at the bottom of the table, or the `-tag caption` tag if displayed at the bottom of the table.
 	</option>
 
+	<option type="boolean" name="autoFilter" default="false" since="1.5.4">
+		Enable Excel's auto filter feature for the header cells in the table allowing the user to quickly filter and sort the exported spreadsheet in Excel. Note that this does not operate in LibreOffice (although the spreadsheet is still readable).
+	</option>
+
+
 
 	<example title="DataTables initialisation: Use the HTML5 Excel button"><![CDATA[
 
@@ -271,5 +276,18 @@ $('#myTable').DataTable( {
 	]
 } );
 
+]]></example>
+
+	<example title="Enable the auto filter option in Excel"><![CDATA[
+
+$('#myTable').DataTable( {
+	buttons: [
+		{
+			extend: 'excelHtml5',
+			autoFilter: true
+		}
+	]
+} );
+
 ]]></example>
 </dt-button>

examples/html5/excelAutoFilter.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<dt-example table-type="html" order="8">
+
+<css lib="datatables buttons"/>
+<js lib="jquery datatables buttons jszip buttons-html5">
+<![CDATA[
+
+$(document).ready( function() {
+	$('#example').DataTable( {
+		dom: 'Bfrtip',
+		buttons: [ {
+			extend: 'excelHtml5',
+			autoFilter: true,
+			sheetName: 'Exported data'
+		} ]
+	} );
+} );
+
+]]>
+</js>
+
+<title lib="Buttons">Excel - auto filter</title>
+
+<info><![CDATA[
+
+Excel has an [AutoFilter](https://support.office.com/en-us/article/use-autofilter-to-filter-your-data-7d87d63e-ebd0-424b-8106-e2ab61133d92) feature which lets the end user quickly filter and sort data in the exported spreadsheet. To enable this feature on the header cells of the exported table, use the `autoFilter` option of the `-button excelHtml5` button type. Please note that the AutoFilter feature does no operate in LibreOffice, but the spreadsheet is still readable - this is a feature specific to Excel.
+
+This example also shows the use of the `sheetName` option which allows the sheet in the exported workbook to be given a defined name.
+
+]]></info>
+
+</dt-example>

examples/html5/excelTextBold.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<dt-example table-type="html" order="8">
+<dt-example table-type="html" order="9">
 
 <css lib="datatables buttons"/>
 <js lib="jquery datatables buttons jszip buttons-html5">

js/buttons.html5.js

@@ -567,8 +567,9 @@ var excelStrings = {
 				'<workbookView xWindow="0" yWindow="0" windowWidth="25600" windowHeight="19020" tabRatio="500"/>'+
 			'</bookViews>'+
 			'<sheets>'+
-				'<sheet name="" sheetId="1" r:id="rId1"/>'+
+				'<sheet name="Sheet1" sheetId="1" r:id="rId1"/>'+
 			'</sheets>'+
+			'<definedNames/>'+
 		'</workbook>',
 
 	"xl/worksheets/sheet1.xml":
@@ -1009,6 +1010,7 @@ DataTable.ext.buttons.excelHtml5 = {
 
 		var that = this;
 		var rowPos = 0;
+		var dataStartRow, dataEndRow;
 		var getXml = function ( type ) {
 			var str = excelStrings[ type ];
 
@@ -1141,8 +1143,6 @@ DataTable.ext.buttons.excelHtml5 = {
 			rowPos++;
 		};
 
-		$( 'sheets sheet', xlsx.xl['workbook.xml'] ).attr( 'name', _sheetname( config ) );
-
 		if ( config.customizeData ) {
 			config.customizeData( data );
 		}
@@ -1171,15 +1171,20 @@ DataTable.ext.buttons.excelHtml5 = {
 			mergeCells( rowPos, data.header.length-1 );
 		}
 
+
 		// Table itself
 		if ( config.header ) {
 			addRow( data.header, rowPos );
 			$('row:last c', rels).attr( 's', '2' ); // bold
 		}
+	
+		dataStartRow = rowPos;
 
 		for ( var n=0, ie=data.body.length ; n<ie ; n++ ) {
 			addRow( data.body[n], rowPos );
 		}
+	
+		dataEndRow = rowPos;
 
 		if ( config.footer && data.footer ) {
 			addRow( data.footer, rowPos);
@@ -1207,6 +1212,29 @@ DataTable.ext.buttons.excelHtml5 = {
 			} ) );
 		}
 
+		// Auto filter for columns
+		$('mergeCells', rels).before( _createNode( rels, 'autoFilter', {
+			attr: {
+				ref: 'A'+dataStartRow+':'+createCellPos(data.header.length-1)+dataEndRow
+			}
+		} ) );
+
+		// Workbook modifications
+		var workbook = xlsx.xl['workbook.xml'];
+
+		$( 'sheets sheet', workbook ).attr( 'name', _sheetname( config ) );
+
+		if ( config.autoFilter ) {
+			$('definedNames', workbook).append( _createNode( workbook, 'definedName', {
+				attr: {
+					name: '_xlnm._FilterDatabase',
+					localSheetId: '0',
+					hidden: 1
+				},
+				text: _sheetname(config)+'!$A$'+dataStartRow+':'+createCellPos(data.header.length-1)+dataEndRow
+			} ) );
+		}
+
 		// Let the developer customise the document if they want to
 		if ( config.customize ) {
 			config.customize( xlsx, config, dt );
@@ -1261,7 +1289,11 @@ DataTable.ext.buttons.excelHtml5 = {
 
 	messageBottom: '*',
 
-	createEmptyCells: false
+	createEmptyCells: false,
+
+	autoFilter: false,
+
+	sheetName: ''
 };
 
 //