Angular 1.5 design pattern for a cached API resource

cachedFetch.service.js

import angular from 'angular';
import assignIn from 'lodash/assignIn';


const meServiceModule = angular.module('meServiceModule', []);

meServiceModule.factory('meService', ['$http', '$q', ($http, $q) => {
  const user = {};
  const state = {
    loaded: false,
    promiseInFlight: false,
    loadingPromise: null,
  };
  
  /**
   * fetchMe - fetches the user's profile from memory or the API
   *
   * fetchMe will try to load the user's profile from the angular service singleton falling back to 
   * fetching from the API. If a request is in flight, fetchMe will return the current request's promise
   * preventing race conditions causing multiple requests to the API.
   * 
   * Usage:
   *     meService.fetchMe().then(user => {
   *       $scope.user = user;
   *     });
   * 
   * @return {Promise} resolves to the user's profile data
   */
  function fetchMe() {
    if (state.promiseInFlight) {
      return state.loadingPromise;
    }
    if (!state.loaded) {
      state.promiseInFlight = true;
      state.loadingPromise = $http({
        method: 'GET',
        url: '/api/me',
      })
        .then(resp => resp.data)
        .then(data => {
          state.promiseInFlight = false;
          state.loaded = true;
          assignIn(user, data);  // your API's data
          return user;
        });
      return state.loadingPromise;
    }
    
    return $q.when(user);  // similar to Promise.resolve(user) 
  }

  return {
    fetchMe,
  };
}]);

export default meServiceModule.name;