Check if array has a particular index in AngularJs

Question

In AngularJS expressions, how can I check if an array has value in a particular index or not? Consider the following example

$scope.arr =['one','two','three'];

In HTML.

<p ng-show="arr[3]!=''">{{arr[3]}}</p>

Mihai Alexandru-Ionut · Accepted Answer · 2017-02-18 10:36:45Z

You have to compare with undefined.

<p ng-show="arr[3]!=undefined">{{arr[3]}}</p>

function MyCtrl($scope) {
  $scope.arr =['one','two','three'];
}

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app>
  <div ng-controller="MyCtrl">
       <p ng-show="arr[2]!=undefined">{{arr[2]}}</p>
  </div>
</div>

Also, you can define a function which check if an array has value in a particular index, using typeof operator.

function isDefined(arrayElement) {
      return typeof arrayElement!== 'undefined';
}

function MyCtrl($scope) {
  $scope.arr =['one','two','three'];
  $scope.isDefined=function(arrayElement){
      return typeof arrayElement!== 'undefined';
  }
}

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app>
  <div ng-controller="MyCtrl">
       <p ng-show="isDefined(arr[3])">{{arr[3]}}</p>
       <p ng-show="!isDefined(arr[3])">undefined</p>
  </div>
</div>

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