fix(common): Fix implementation of 'pick' -- use hasOwnProperty

Closes #53

Author: christopherthielen

src/common/common.ts

@@ -234,10 +234,9 @@ export function ancestors(first: StateObject, second: StateObject) {
 
 /**
  * Return a copy of the object only containing the whitelisted properties.
-
- * @example
- * ```
  *
+ * #### Example:
+ * ```
  * var foo = { a: 1, b: 2, c: 3 };
  * var ab = pick(foo, ['a', 'b']); // { a: 1, b: 2 }
  * ```
@@ -246,8 +245,7 @@ export function ancestors(first: StateObject, second: StateObject) {
  */
 export function pick(obj: Obj, propNames: string[]): Obj {
   let copy = {};
-  // propNames.forEach(prop => { if (obj.hasOwnProperty(prop)) copy[prop] = obj[prop] });
-  propNames.forEach(prop => { if (isDefined(obj[prop])) copy[prop] = obj[prop] });
+  propNames.forEach(prop => { if (obj.hasOwnProperty(prop)) copy[prop] = obj[prop] });
   return copy;
 }
 

test/transitionSpec.ts

@@ -864,6 +864,21 @@ describe('transition', function () {
       done();
     });
 
+    it('should not inherit previous params when new params are passed', async(done) => {
+      router.stateRegistry.register({
+        name: 'foo',
+        url: '?fooParam',
+      });
+
+      await $state.go('foo', { fooParam: 'abc' });
+      expect(router.globals.params).toEqualValues({ fooParam: 'abc' });
+
+      await $state.go('foo', { fooParam: undefined });
+      expect(router.globals.params).toEqualValues({ fooParam: undefined });
+
+      done();
+    });
+
     it('should not inherit params whose type has inherit: false', async(done) => {
       router.urlService.config.type('inherit', {
         inherit: true, encode: x => x, decode: x => x, is: () => true, equals: equals, pattern: /.*/, raw: false,