Merge pull request lenage#2 from AndreLion/upload-progress-callback

Add progress callback

index.js

@@ -91,6 +91,7 @@ var ReactQiniu = React.createClass({
         if (!file || file.size === 0) return null;
         var url;
         var key = file.preview.split('/').pop() + '.' + file.name.split('.').pop();
+        var _this = this;
         if (this.props.prefix) {
             key = this.props.prefix  + key;
         }
@@ -102,11 +103,20 @@ var ReactQiniu = React.createClass({
             .field('x:size', file.size)
             .attach('file', file, file.name)
             .set('Accept', 'application/json')
-            .on('progress',  function (e) { file.progress = e.percent;})
+            .on('progress',  function (e) {
+                if(_this.isFunction(file.onprogress)){
+                    file.onprogress(e.percent);
+                }
+            })
             .promise()
         return promise;
     },
 
+    isFunction: function(fn) {
+        var getType = {};
+        return fn && getType.toString.call(fn) === '[object Function]';
+    },
+
     render: function() {
         var className = this.props.className || 'dropzone';
         if (this.state.isDragActive) {