It is used to format the value of the expression to display the output. AngularJS enables us to apply filter. It can be added to expressions by using the pipe character |, followed by a filter.

BY Best Interview Question ON 19 Jun 2020

Example

<div ng-app="myApp" ng-controller="personCtrl">    
<p>The name is {{ firstName | uppercase }}</p>    
</div>    
<script>    
angular.module('myApp', []).controller('personCtrl', function($scope) {    
    $scope.firstName = "Umesh",    
    $scope.lastName = "Singh"
});
</script>