check null,empty or undefined angularjs

Question

I am creating a project using angularjs.I have variable like

$scope.test = null
$scope.test = undefined
$scope.test = \"\"

I want to check all

Answer 1

You can do

if($scope.test == null || $scope.test === ""){
  // null == undefined
}

if false, 0 and NaN can also be considered as false values you can just do

if($scope.test){
 //not any of the above
}