AngularJS StateProvider: How to Handle 'Otherwise' Route?

When working with AngularJS StateProvider, it's common to define routes and handle them through the $stateProvider. However, sometimes there may be scenarios where a route is not defined and the user is redirected to a default or error page. This is where the 'otherwise' route comes into play.

The 'otherwise' route is used to handle any undefined routes in the application. It's defined using the $urlRouterProvider.otherwise() method. This method takes a function as a parameter, which is called when a user tries to access an undefined route.

Here's an example of how to use the 'otherwise' route:

angular.module('myApp', ['ui.router'])
.config(function($stateProvider, $urlRouterProvider) {
  $stateProvider
    .state('home', {
      url: '/home',
      templateUrl: 'home.html'
    })
    .state('about', {
      url: '/about',
      templateUrl: 'about.html'
    });

  $urlRouterProvider.otherwise(function($injector, $location) {
    var state = $injector.get('$state');
    state.go('home');
  });
});

In this example, if the user tries to access an undefined route, they will be redirected to the 'home' state. The $injector.get('$state') method is used to retrieve the $state service, which is then used to transition to the 'home' state.

Overall, the 'otherwise' route is a useful feature to handle undefined routes in an AngularJS application. With this feature, you can ensure that users are always directed to a default or error page when they try to access an undefined route.