src/core/query.js in entityjs-0.4.2 vs src/core/query.js in entityjs-0.4.3

@@ -365,9 +365,18 @@
         }
       });
       
       return val;
     }
+
+    p.sum = function(method, context){
+        var val = 0;
+
+        this.each(function(e, i, l){
+            val += method.call(context || this, e, i, l);
+        });
+        return val;
+    }
     
     //without this filter would return a normal array.
     p.filter = function(){
       return re(Array.prototype.filter.apply(this, arguments));
     }
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