用回车键向无序列表添加不重复的数据

<input type="text" ng-model="shuru" ng-keyup="mykey($event)"/>
 <ul>
  <li ng-repeat="x in list1">{{x}}</li>
 </ul>
 <script>
  var mo = angular.module("myApp",[]);
  mo.controller("myCtrl",function($scope){
   //先定义几个数组的内容
   $scope.list1 = ["1","11","111"];
   $scope.mykey = function(e){
    //获取回车编码
    var keycode = window.event?e.keyCode:e.which;
    if(keycode==13){
     $scope.myClick();//如果等于回车编码执行方法
    }
   };
  $scope.myClick = function(){
   //不重复添加
   if(!arrindex($scope.list1,$scope.shuru)){
    $scope.list1.push($scope.shuru);
   }
  };
  });
  function arrindex(arr,obj){
   //判断是否重复
   var i = arr.length;
   while(i--){
    if(arr[i]===obj){
     alert("重复了");
     return true;     
    }
   }
   return false;
  }
 </script>