Undefined or null for AngularJS
angularjs, null, undefined
Solution
You can always add it exactly for your application
angular.isUndefinedOrNull = function(val) {
return angular.isUndefined(val) || val === null
}
Problem
When I write watch handling functions I check newVal param on `undefined` and `null`. Why does AngularJS have such a behavior, but doesn't have particular utility method? So there is `angular.isUndefined` but not `angular.isUndefinedOrNull`. It isn't hard to implement that by hand but how extend angular to have that function in each controller? Tnx. Edit: The example: ``` $scope.$watch("model", function(newVal) { if (angular.isUndefined(newVal) || newVal == null) return; // do somethings with newVal } ``` Is it common accepted practice to handle such a way? Edit 2: The JSFiddle example (http://jsfiddle.net/ubA9r/): ``` <div ng-app="App"> <div ng-controller="MainCtrl"> <select ng-model="model" ng-options="m for m in models"> <option value="" class="ng-binding">Choose model</option> </select> {{model}} </div> </div> var app = angular.module("App", []); var MainCtrl = function($scope) { $scope.models = ['Apple', 'Banana']; $scope.$watch("model", function(newVal) { console.log(newVal); }); }; ```