Capitalize the first letter of string in AngularJs

var app = angular.module('app', []);

app.controller('Ctrl', function ($scope) {
   $scope.msg = 'hello, world.';
});

app.filter('capitalize', function() {
    return function(input) {
      return (angular.isString(input) && input.length > 0) ? input.charAt(0).toUpperCase() + input.substr(1).toLowerCase() : input;
    }
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="app">
    <div ng-controller="Ctrl">
        <p><b>My Text:</b> {{msg | capitalize}}</p>
    </div>
</div>