# AngularJS – isUndefined() method

PythonServer Side ProgrammingProgramming

The isUndefined() method in AngularJS basically checks if a reference is defined or not. This method will return True if the reference passed inside the function is not defined or undefined, else it will return False.

## Syntax

angular.isUndefined(value)

## Example − Check if the reference isUndefined or not

Create a file "isUndefined.html.3" in your Angular project directory and copy-paste the following code snippet.

<!DOCTYPE html>
<html>
<title>angular.isUndefined()</title>

</script>

<body ng-app="app" style="text-align:center">
<h1 style="color:green">
Welcome to Tutorials Point
</h1>
<h2>AngularJS | angular.isUndefined()</h2>

<div ng-controller="example">
<b>Name: {{name}}</b>
<br><br>
{{isUndefined}}
<br><br>
<b>Name: {{name2}}</b>
<br><br>
{{isUndefined1}}
</div>

<!-- Script for passing the values and checking... -->
<script>
var app = angular.module("app", []);
app.controller('example',['$scope', function ($scope)
{
// Defining the keys & values
$scope.name = "SIMPLY LEARNING";$scope.name2;

$scope.isUndefined = angular.isUndefined($scope.name) == true
? "$scope.name is Undefined." : "$scope.name is Defined.";

$scope.isUndefined1 = angular.isUndefined($scope.name2)== true
? "$scope.name2 is Undefined." : "$scope.name2 is Defined.";
}]);
</script>
</body>
</html>

## Output

To run the above code, just go to your file and run it as a normal HTML file. You will see the following output on the browser window.

In the code, $scope.name is defined, whereas$scope.name2 is not undefined. Hence, we got this output.

Published on 08-Oct-2021 10:48:32