Setting AngularJS app configurations after a service has been called - angularjs

Question

I am using $urlRouterProvider service in my app.config to define the default routes in my AngularJS application. I define it as follows:
app.config(function ($stateProvider, $urlRouterProvider) {
$urlRouterProvider
.when('/', '/history')
.otherwise('/history');
$stateProvider
.state('tabs', {
abstract: true,
url: '/',
template: '<my-tab></my-tab>',
onEnter: function(){console.log("enter");}
})
});
My problem is that I want to set these routes after a Boolean variable flag is fetched from database using a custom service (databaseService). If the flag is true, it should be:
$urlRouterProvider
.when('/', '/history')
.otherwise('/history');
and if flag is false, it should be:
$urlRouterProvider
.when('/', '/future')
.otherwise('/future');
How can I achieve this? I am not able to use a custom service in app.config function. Also I can't set configurations in my service because config gets set before a service is loaded. Please help!

Answer 1

Assuming you're going to change this once at the start of the application you could to the following (docs):
var routerProvider = null; // reference router for run phase
angular
.module('app')
.config(config)
.factory('databaseService', databaseService)
.run(run);
config.$inject = ['$urlRouterProvider'];
run.$inject = ['$urlRouter', 'databaseService'];
function config($urlRouterProvider) {
$urlRouterProvider.deferIntercept();
routerProvider = $urlRouterProvider;
}
function databaseService() {
return {
getDbFlag: function() {
// connect to db and fetch data
}
};
}
function run($urlRouter, databaseService) {
databaseService.getDbFlag()
.then(function (serviceData) {
// set the route with data from the DB
routerProvider.otherwise(serviceData.route);
$urlRouter.sync();
$urlRouter.listen();
});
}