Optional output type

README.md

@@ -44,6 +44,7 @@ Quickly and easily create PowerPoint presentations with a few simple JavaScript
   - [Saving a Presentation](#saving-a-presentation)
     - [Client Browser](#client-browser)
     - [Node.js](#nodejs-1)
+    - [Specific output type](#specific-output-type)
 - [Presentations: Adding Objects](#presentations-adding-objects)
   - [Adding Charts](#adding-charts)
     - [Chart Types](#chart-types)
@@ -287,7 +288,17 @@ pptx.save( 'Node_Demo', saveCallback );
 pptx.save( 'http', streamCallback );
 ```
 
-Saving multiple Presentations:  
+### Specific output type
+When a save callback function is specified (no matter whether on a client or in Node), an extra parametr can be passed – `outputType`.
+This parameter accepts any value of [the JSzip supported formats](https://stuk.github.io/jszip/documentation/api_jszip/generate_async.html). For example:
+
+```javascript
+pptx.save( 'whatever', function(content) {
+  console.log(content);
+}, 'base64');
+```
+
+Saving multiple Presentations:
 * In order to generate a new, unique Presentation just create a new instance of the library then add objects and save as normal.
 
 ```javascript

dist/pptxgen.js

@@ -119,6 +119,9 @@ var PptxGenJS = function(){
 	var DEF_SLIDE_MARGIN_IN = [0.5, 0.5, 0.5, 0.5]; // TRBL-style
 	var DEF_CHART_GRIDLINE = { color: "888888", style: "solid", size: 1 };
 
+	/** @see https://stuk.github.io/jszip/documentation/api_jszip/generate_async.html */
+	var ALLOWED_OUTPUT_TYPES = ['base64', 'binarystring', 'uint8array', 'arraybuffer', 'blob', 'nodebuffer'];
+
 	// A: Create internal pptx object
 	var gObjPptx = {};
 
@@ -158,7 +161,7 @@ var PptxGenJS = function(){
 	/**
 	 * DESC: Export the .pptx file
 	 */
-	function doExportPresentation(callback) {
+	function doExportPresentation(callback, outputType) {
 		var arrChartPromises = [];
 		var intSlideNum = 0, intRels = 0;
 
@@ -422,7 +425,10 @@ var PptxGenJS = function(){
 		Promise.all( arrChartPromises )
 		.then(function(arrResults){
 			var strExportName = ((gObjPptx.fileName.toLowerCase().indexOf('.ppt') > -1) ? gObjPptx.fileName : gObjPptx.fileName+gObjPptx.fileExtn);
-			if ( NODEJS ) {
+			if ( outputType && ALLOWED_OUTPUT_TYPES.indexOf(outputType) >= 0) {
+				zip.generateAsync({ type: outputType }).then(callback);
+			}
+			else if ( NODEJS ) {
 				if ( callback ) {
 					if ( strExportName.indexOf('http') == 0 ) {
 						zip.generateAsync({type:'nodebuffer'}).then(function(content){ callback(content); });
@@ -2830,7 +2836,7 @@ var PptxGenJS = function(){
 	 * Export the Presentation to an .pptx file
 	 * @param {string} [inStrExportName] - Filename to use for the export
 	 */
-	this.save = function save(inStrExportName, callback) {
+	this.save = function save(inStrExportName, callback, outputType) {
 		var intRels = 0, arrRelsDone = [];
 
 		// STEP 1: Set export title (if any)
@@ -2864,7 +2870,7 @@ var PptxGenJS = function(){
 		});
 
 		// STEP 3: Export now if there's no images to encode (otherwise, last async imgConvert call above will call exportFile)
-		if ( intRels == 0 ) doExportPresentation(callback);
+		if ( intRels == 0 ) doExportPresentation(callback, outputType);
 	};
 
 	/**