NavigationExperimental reducer

import { NavigationExperimental } from 'react-native';
import _ from 'lodash';
import { PUSH_ROUTE, POP_ROUTE } from './actions';
import { LOGIN_SUCCESS, LOGOUT_SUCCESS } from '../auth/actions';

const { StateUtils: NavigationStateUtils } = NavigationExperimental;

const initialState = {
  index: 0,
  key: 'root',
  routes: [
    {
      key: 'home',
      title: 'Homepage',
    },
  ],
  redirect: { key: 'home', title: 'Homepage' },
  authed: false,
};

export default function (state = initialState, action) {
  let newState;
  switch (action.type) {
    case LOGIN_SUCCESS:
      newState = _.cloneDeep(state);
      newState.authed = true;
      if (newState.routes[state.index].key === 'login')
        return useRedirect(newState);
      return newState;
    case LOGOUT_SUCCESS:
      newState = _.cloneDeep(state);
      newState.authed = false;
      return popToRoute(newState, 'home');
    case PUSH_ROUTE:
      return pushRoute(state, action.route);
    case POP_ROUTE:
      return popRoute(state);
    default:
      return state;
  }
}

function popRoute(state) {
  if (state.index === 0)
    return state;
  if (state.routes[state.index].key === 'login' && state.routes[state.index - 1].key === state.redirect.key)
    return popToRoute(state, state.routes[state.index - 2].key);
  return NavigationStateUtils.pop(state);
}

function pushRoute(state, route) {
  if (route.requireAuth === true && !state.authed)
    return setLogin(state, route);
  const index = indexOfRoute(state, route.key);
  if (index !== -1)
    return NavigationStateUtils.jumpTo(state, route.key);
  return NavigationStateUtils.push(state, route);
}

function indexOfRoute(state, key) {
  return NavigationStateUtils.indexOf(state, key);
}

function popToRoute(state, key) {
  const newState = state;
  const index = indexOfRoute(state, key);
  newState.routes = newState.routes.slice(0, index + 1);
  newState.index = index;
  return NavigationStateUtils.jumpToIndex(newState, index);
}

function setLogin(state, route) {
  const newState = pushRoute(state, { key: 'login', title: 'Login Page' });
  newState.redirect = { key: route.key, title: route.title };
  return newState;
}

function useRedirect(state) {
  const newState = popRoute(state);
  const redirect = newState.redirect;
  redirect.requireAuth = true;
  return pushRoute(newState, redirect);
}