$filter-2

$filter('lowercase') will convert "LEARNKODE" to lowercase. See the code snippet for $filter('lowercase'):

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Welcome in the AngularJS</title>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.2/angular.min.js"></script>
</head>
<body ng-app="app">
    <div ng-controller="controllerName">
        <h3>{{ originalText }}</h3>
        <h3>{{ filteredText }}</h3>
    </div>
</body>
</html>
<script>
    var app = angular.module("app", []);
    app.controller('controllerName', ['$scope', '$filter', function ($scope, $filter) {
        $scope.originalText = 'LEARNKODE';
        $scope.filteredText = $filter('lowercase')($scope.originalText);
    }]);
</script>

Output