Added toBlob. Updated toImage to return a Promise.

konva.js

@@ -3987,7 +3987,7 @@
        * @method
        * @name Konva.Node#toCanvas
        * @param {Object} config
-       * @param {Function} config.callback function executed when the composite has completed
+       * @param {Function} [config.callback] function executed when the composite has completed
        * @param {Number} [config.x] x position of canvas section
        * @param {Number} [config.y] y position of canvas section
        * @param {Number} [config.width] width of canvas section
@@ -4036,13 +4036,13 @@
           return url;
       }
       /**
-       * converts node into an image.  Since the toImage
-       *  method is asynchronous, a callback is required.  toImage is most commonly used
+       * converts node into an image.  Since the toImage method is asynchronous,
+	   *  the method returns a promise or a callback is required.  toImage is most commonly used
        *  to cache complex drawings as an image so that they don't have to constantly be redrawn
        * @method
        * @name Konva.Node#toImage
        * @param {Object} config
-       * @param {Function} config.callback function executed when the composite has completed
+       * @param {Function} [config.callback] function executed when the composite has completed
        * @param {String} [config.mimeType] can be "image/png" or "image/jpeg".
        *  "image/png" is the default
        * @param {Number} [config.x] x position of canvas section
@@ -4063,17 +4063,53 @@
        *     // do stuff with img
        *   }
        * });
+       * OR
+       * var img = await node.toImage({});
+	   * @returns {Promise<Image>}
        */
       toImage(config) {
-          if (!config || !config.callback) {
-              throw 'callback required for toImage method config argument';
-          }
           var callback = config.callback;
           delete config.callback;
-          Util._urlToImage(this.toDataURL(config), function (img) {
-              callback(img);
+          return new Promise(resolve=>{
+        	  Util._urlToImage(this.toDataURL(config), function (img) {
+				  resolve(img);
+            	  callback(img);
+              });
           });
       }
+      /**
+       * Converts node into a blob.
+       * @method
+       * @name Konva.Node#toBlob
+       * @param {Object} config
+       * @param {Function} [config.callback] function executed when the composite has completed
+       * @param {Number} [config.x] x position of canvas section
+       * @param {Number} [config.y] y position of canvas section
+       * @param {Number} [config.width] width of canvas section
+       * @param {Number} [config.height] height of canvas section
+       * @param {Number} [config.pixelRatio] pixelRatio of output canvas. Default is 1.
+       * You can use that property to increase quality of the image, for example for super hight quality exports
+       * or usage on retina (or similar) displays. pixelRatio will be used to multiply the size of exported image.
+       * If you export to 500x500 size with pixelRatio = 2, then produced image will have size 1000x1000.
+       * @param {Boolean} [config.imageSmoothingEnabled] set this to false if you want to disable imageSmoothing
+       * @example
+       * var blob = await node.toBlob();
+       * @returns {Promise<Blob>}
+       */
+	  toBlob(config = {}){
+          const callback = config.callback;
+          delete config.callback;
+          return new Promise((resolve, reject)=>{
+              try{
+                  this.toCanvas(config).toBlob(blob => {
+                      resolve(blob);
+                      callback?.(blob);
+                  });
+              } catch(err){
+                  reject(err);
+              }
+          });
+	  }
       setSize(size) {
           this.width(size.width);
           this.height(size.height);