undefined

<html>
  <head>
    <!--<script src="//unpkg.com/show-current-browser-url"></script>-->
    <script src="//unpkg.com/angular@1.5/angular.js"></script>
    <script src="//unpkg.com/angular-ui-router@1.0.0-beta.3/release/angular-ui-router.js"></script>
    <script src="app.js"></script>
  </head>
  <body ng-app="routerApp">
    <a ui-sref="home">Home</a>
    <a ui-sref="about({ meId:1})">About</a>
    <ui-view></ui-view>
  </body> 
</html>

angular
  .module('routerApp', ['ui.router'])
  .config(['$stateProvider','$urlRouterProvider',function($stateProvider,$urlRouterProvider){
    
	  $stateProvider
	  
	  .state('home',{
		  url : '/home',
		  templateUrl : 'home.html',
		  controller: function($state,$stateParams){
        var vm = this;
        vm.go = function(){
          $state.go('about', {someParam : 'about page loading'});
        };
        console.log('about param:', $stateParams);
		  }
	  })

	  .state('about',{
	  	url : '/about/{meId}',
		  templateUrl : 'about.html',
		  controller: function($stateParams){
		    if($stateParams.meId == 1) {
		      var vm = this;
		       vm.meId = {
		         id: $stateParams.meId,
		         naam: 'audrey',
		         nickname: 'audi'
		       }
		    }
		  }
	  });
	$urlRouterProvider.otherwise('/home');
}])

The angular-ui-router "Hello World" app

<h1>Home</h1>

<h1>About me</h1>

{{meId.id}}
{{meId.naam}}
{{meId.nickname}}