Copy from react-navigation

packages/core/src/getNavigation.js

@@ -0,0 +1,54 @@
+import getNavigationActionCreators from './routers/getNavigationActionCreators';
+import getChildNavigation from './getChildNavigation';
+
+export default function getNavigation(
+  router,
+  state,
+  dispatch,
+  actionSubscribers,
+  getScreenProps,
+  getCurrentNavigation
+) {
+  const actions = router.getActionCreators(state, null);
+
+  const navigation = {
+    actions,
+    router,
+    state,
+    dispatch,
+    getScreenProps,
+    getChildNavigation: childKey =>
+      getChildNavigation(navigation, childKey, getCurrentNavigation),
+    isFocused: childKey => {
+      const { routes, index } = getCurrentNavigation().state;
+      if (childKey == null || routes[index].key === childKey) {
+        return true;
+      }
+      return false;
+    },
+    addListener: (eventName, handler) => {
+      if (eventName !== 'action') {
+        return { remove: () => {} };
+      }
+      actionSubscribers.add(handler);
+      return {
+        remove: () => {
+          actionSubscribers.delete(handler);
+        },
+      };
+    },
+    dangerouslyGetParent: () => null,
+  };
+
+  const actionCreators = {
+    ...getNavigationActionCreators(navigation.state),
+    ...actions,
+  };
+
+  Object.keys(actionCreators).forEach(actionName => {
+    navigation[actionName] = (...args) =>
+      navigation.dispatch(actionCreators[actionName](...args));
+  });
+
+  return navigation;
+}