ng-model: empty strings should be null

Question

If I use ng-model for an input field and empty it, angular sets it to '' instead of null even if it was null before.

This is a problem in my case because I need to send null to the server if the input field is empty, and not ''.

Is there a way to tell angular setting "empty" input models to null?

Answer 1

You may want to $watch for the empty value and set it to null:

<input type="text" ng-model="test.value" /> 

$scope.$watch('test.value', function (newValue, oldValue) {   if(newValue === "")     $scope.test.value = null; }); 

Another way would be to use a custom directive and apply a $parsers in it:

<input type="text" ng-model="test.value" empty-to-null /> 

myApp.directive('emptyToNull', function () {     return {         restrict: 'A',         require: 'ngModel',         link: function (scope, elem, attrs, ctrl) {             ctrl.$parsers.push(function(viewValue) {                 if(viewValue === "") {                     return null;                 }                 return viewValue;             });         }     }; });