Added exists method to pang

README.md

@@ -60,7 +60,12 @@ $scope.objects.update(object);
 
 If you would only like to fetch objects with a certain condition, use `where`.
 ``` javascript
-$scope.objects = pang.Collection(ParseTable).where({'isAwesome', true}).build();
+$scope.objects = pang.Collection(ParseTable).where('isAwesome', true).build();
+```
+
+To fetch objects if they exist, use `exist`.
+``` javascript
+$scope.objects = pang.Collection(ParseTable).exists('hasAwesomePower', true).build();
 ```
 
 Sort the objects with `order`.

pang.js

@@ -433,6 +433,19 @@ angular.module('pang', []).factory('pang', function($rootScope) {
       } // pangCollection.where()
 
 
+      /***************************************************************
+      *
+      * pangCollection.exists()
+      *
+      *  Add the attributes to the list of matchs to add to the query.
+      *
+      ***************************************************************/
+      pangCollection.exists = function(key, existence) {
+        pangCollection.exists[key] = existence != null ? existence : true;
+        return pangCollection;
+      } // pangCollection.exists()
+
+
       /***************************************************************
       *
       * pangCollection.order()
@@ -477,6 +490,19 @@ angular.module('pang', []).factory('pang', function($rootScope) {
           query.equalTo(match, pangCollection.queryMatches[match]);
         }
 
+        //add all the needed existences to the query
+        for(key in pangCollection.exists) {
+
+          //ascending
+          if(pangCollection.exists[key] == true) {
+            query.exists(key);
+
+          //descending
+          } else {
+            query.doesNotExist(key);
+          }
+        }
+
         //add sorting to the query which has been specified by the user with 'order'
         for(key in pangCollection.orders) {