fix(globals): Use shallow copy to update the globals.params / $state.params object

Previously, the `globals.params` object was updated using a deep copy.
This causes problems when object-type parameter values aren't cloneable.

Now, the parameter values are copied to the `globals.params` object using a shallow copy, i.e., `Object.assign`.
This is consistent with parameter handling in the `PathNode` code also.

If this commit is causing problems, it is likely that app code is mutating
the existing object parameters and then calling `state.go` with the mutated
parameters.  Recommend making a clone of the params before calling `state.go`.

Closes #74

Author: christopherthielen

src/common/common.ts

@@ -16,7 +16,6 @@ let w: any = typeof window === 'undefined' ? {} : window;
 let angular = w.angular || {};
 export const fromJson = angular.fromJson || JSON.parse.bind(JSON);
 export const toJson = angular.toJson || JSON.stringify.bind(JSON);
-export const copy = angular.copy || _copy;
 export const forEach = angular.forEach || _forEach;
 export const extend = Object.assign || _extend;
 export const equals = angular.equals || _equals;
@@ -528,11 +527,8 @@ export function tail<T>(arr: T[]): T {
 
 /**
  * shallow copy from src to dest
- *
- * note: This is a shallow copy, while angular.copy is a deep copy.
- * ui-router uses `copy` only to make copies of state parameters.
  */
-function _copy(src: Obj, dest: Obj) {
+export function copy(src: Obj, dest?: Obj) {
   if (dest) Object.keys(dest).forEach(key => delete dest[key]);
   if (!dest) dest = {};
   return extend(dest, src);

src/globals.ts

@@ -7,8 +7,6 @@ import {StateDeclaration} from "./state/interface";
 import {StateObject} from "./state/stateObject";
 import {Transition} from "./transition/transition";
 import {Queue} from "./common/queue";
-import {TransitionService} from "./transition/transitionService";
-import {copy} from "./common/common";
 import { Disposable } from './interface';
 
 /**

test/stateServiceSpec.ts

@@ -426,6 +426,27 @@ describe('stateService', function () {
 
           done();
         });
+
+        it('performs a shallow copy to $stateParams (for object parameters)', async (done) => {
+          const x = { foo: '123' }, y = { bar: 'abc' };
+          await $state.go('D', { x, y });
+
+          expect($state.params.x).toBe(x);
+          expect($state.params.y).toBe(y);
+
+          done();
+        });
+
+        it('updates the object reference in-place', async (done) => {
+          const params = $state.params;
+          const x = { foo: '123' };
+          await $state.go('D', { x });
+
+          expect($state.params.x).toBe(x);
+          expect(params).toBe($state.params);
+
+          done();
+        });
       });
     });
 
@@ -952,4 +973,4 @@ describe('stateService', function () {
     });
 
   });
-});
+});