AngularJS angular.isUndefined() Function (original) (raw)

Last Updated : 08 Nov, 2022

The angular.isUndefined() function in AngularJS is used to determine the value inside isUndefined function is undefined or not. It returns true if the reference is undefined otherwise returns false.

Syntax:

angular.isUndefined( value )

Parameter value:

value: It is used to reference the value to check whether the value is defined or undefined.

Return Value: It returns true if the value passed is undefined else returns false.

Example 1: This example uses angular.isUndefined() function in AngularJS to determine the value inside the isUndefined function is undefined or not.

HTML `

angular.isUndefined() function

GeeksforGeeks

angular.isUndefined()

<div ng-controller="isDefinedController">
    <b>Date:</b> {{date}}<br><br>
    {{isUndefined}}
    <br><br><br>
    <b>Date1:</b> {{date1}}<br><br>
    {{isUndefined1}}
</div>

<script>
    var app = angular.module("app", []);
    app.controller('isDefinedController',
        ['$scope', function ($scope) {
            $scope.date = new Date;
            $scope.date1;

            <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>c</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi mathvariant="normal">.</mi><mi>i</mi><mi>s</mi><mi>U</mi><mi>n</mi><mi>d</mi><mi>e</mi><mi>f</mi><mi>i</mi><mi>n</mi><mi>e</mi><mi>d</mi><mo>=</mo><mi>a</mi><mi>n</mi><mi>g</mi><mi>u</mi><mi>l</mi><mi>a</mi><mi>r</mi><mi mathvariant="normal">.</mi><mi>i</mi><mi>s</mi><mi>U</mi><mi>n</mi><mi>d</mi><mi>e</mi><mi>f</mi><mi>i</mi><mi>n</mi><mi>e</mi><mi>d</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">scope.isUndefined = angular.isUndefined(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">sco</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord">.</span><span class="mord mathnormal">i</span><span class="mord mathnormal">s</span><span class="mord mathnormal" style="margin-right:0.10903em;">U</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">in</span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">an</span><span class="mord mathnormal">gu</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord">.</span><span class="mord mathnormal">i</span><span class="mord mathnormal">s</span><span class="mord mathnormal" style="margin-right:0.10903em;">U</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">in</span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mopen">(</span></span></span></span>scope.date)
                == true ? "$scope.date is Undefined."
                : "$scope.date is not Undefined.";

            <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>c</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi mathvariant="normal">.</mi><mi>i</mi><mi>s</mi><mi>U</mi><mi>n</mi><mi>d</mi><mi>e</mi><mi>f</mi><mi>i</mi><mi>n</mi><mi>e</mi><mi>d</mi><mn>1</mn><mo>=</mo><mi>a</mi><mi>n</mi><mi>g</mi><mi>u</mi><mi>l</mi><mi>a</mi><mi>r</mi><mi mathvariant="normal">.</mi><mi>i</mi><mi>s</mi><mi>U</mi><mi>n</mi><mi>d</mi><mi>e</mi><mi>f</mi><mi>i</mi><mi>n</mi><mi>e</mi><mi>d</mi><mo stretchy="false">(</mo></mrow><annotation encoding="application/x-tex">scope.isUndefined1 = angular.isUndefined(</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal">sco</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord">.</span><span class="mord mathnormal">i</span><span class="mord mathnormal">s</span><span class="mord mathnormal" style="margin-right:0.10903em;">U</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">in</span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mord">1</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal">an</span><span class="mord mathnormal">gu</span><span class="mord mathnormal" style="margin-right:0.01968em;">l</span><span class="mord mathnormal">a</span><span class="mord mathnormal" style="margin-right:0.02778em;">r</span><span class="mord">.</span><span class="mord mathnormal">i</span><span class="mord mathnormal">s</span><span class="mord mathnormal" style="margin-right:0.10903em;">U</span><span class="mord mathnormal">n</span><span class="mord mathnormal">d</span><span class="mord mathnormal">e</span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">in</span><span class="mord mathnormal">e</span><span class="mord mathnormal">d</span><span class="mopen">(</span></span></span></span>scope.date1)
                == true ? "$scope.date1 is Undefined."
                : "$scope.date1 is not Undefined.";
        }]);
</script>

Output:

Example 2: This example uses angular.isUndefined() function in AngularJS by verifying the defined & undefined values.

HTML `

angular.isUndefined() function