validation - Prevent removing field in json if field is empty and field is required angularjs -

i wondering if theres way prevent removing field in json.

for example have form:

<form name="frmsample"> <input type="text" required ng-model="user.firstname" /> <input type="text" ng-model="user.lastname" /> </form> 

so if field not empty object {"firstname":"not empty","lastname":"not empty"} need make when empty: {"firstname":"","lastname":""} if required, not {"lastname":""}

is posible?

thanks

if understand question correctly, set values in controller this:

angular.module('myapp')          .controller('myctrl', function ($scope) {     // ...     $scope.user = {        firstname: '',        lastname: '',    };     // ...  }); 

incidentally, it's required attribute on user.firstname input field that's causing firstname property become undefined. if remove required attribute, problem goes away:

<form name="frmsample">     <input type="text" ng-model="user.firstname" />     <input type="text" ng-model="user.lastname" /> </form>