add shuffle method; Ref #719

js/isotope.js

@@ -549,6 +549,17 @@ function isotopeDefinition( Outlayer, getSize, matchesSelector, Item, LayoutMode
     }
   };
 
+  Isotope.prototype.shuffle = function() {
+    // update random sortData
+    for ( var i=0, len = this.items.length; i < len; i++ ) {
+      var item = this.items[i];
+      item.sortData.random = Math.random();
+    }
+    this.options.sortBy = 'random';
+    this._sort();
+    this._layout();
+  };
+
   /**
    * trigger fn without transition
    * kind of hacky to have this in the first place