Use arrow function instead of bind

Author: brentvatne

src/views/CardStack/CardStack.js

@@ -129,7 +129,7 @@ class CardStack extends React.Component {
       const screenNavigation = addNavigationHelpers({
         dispatch: navigation.dispatch,
         state: scene.route,
-        isFocused: this._isRouteFocused.bind(this, scene.route),
+        isFocused: () => this._isRouteFocused(scene.route),
         addListener: this._childEventSubscribers[scene.route.key],
       });
       screenDetails = {

src/views/Drawer/DrawerView.js

@@ -108,7 +108,7 @@ export default class DrawerView extends React.PureComponent {
     this._screenNavigationProp = addNavigationHelpers({
       dispatch: navigation.dispatch,
       state: navigationState,
-      isFocused: this._isRouteFocused.bind(this, navigationState),
+      isFocused: () => this._isRouteFocused(navigationState),
       addListener: this._childEventSubscribers[navigationState.key],
     });
   };