remove dependency on assert (#698)

package.json

@@ -36,7 +36,6 @@
     }
   ],
   "dependencies": {
-    "assert": "^1.3.0",
     "react-native-tabs": "^1.0.2"
   },
   "devDependencies": {

src/Actions.js

@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  */
-import assert from 'assert';
+import { assert } from './Util';
 import Scene from './Scene';
 export const JUMP_ACTION = 'jump';
 export const PUSH_ACTION = 'push';

src/Reducer.js

@@ -19,7 +19,7 @@ import {
   REFRESH_ACTION,
 } from './Actions';
 
-import assert from 'assert';
+import { assert } from './Util';
 import { getInitialState } from './State';
 
 // WARN: it is not working correct. rewrite it.

src/State.js

@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  */
-import assert from 'assert';
+import { assert } from './Util';
 
 function getStateFromScenes(route, scenes, props) {
   const getters = [];

src/Util.js

@@ -0,0 +1,5 @@
+export function assert(expr, failDescription) {
+  if (!expr) {
+    throw new Error(`[react-native-router-flux] ${failDescription}`);
+  }
+}