Switch between mock and real service implementation

DonutRepositoryMock.js

var donutModule = angular.module('donuts', []);

window.DonutRepository = function($http) {
  this.$http = $http;
  
  this.fetchDonuts = function(size, filling, glaze, hasHole) {
   var url = '/api/donuts/list?size=' + size +
     '&filling=' + filling +
     '&glaze=' + glaze +
     '&hole=' + hasHole ? 1 : 0;
   // invoke real service
   return this.$http.get(url)
    .then(function(response) {
      return response.data.results;
    });
  };
}

window.DonutRepositoryMock = function($http) {
  this.$http = $http;
  
  this.fetchDonuts = function(size, filling, glaze, hasHole) {
    // just get data from a flat JSON file
    return this.$http.get('/mockdata/donut/fetch.json')
    .then(function(response) {
      return response.data.results;
    });
  };
}
 
donutModule.factory('donutRepository',
  ['$http', 'configModel', function($http, configModel) {
  if (configModel.mocksEnabled) {
    return new DonutRepositoryMock($http);
  } else {
    return new DonutRepository($http);
  }
}]);