Tree checkboxes in AngularJS

I am trying to create tree checkboxes like:

• o Master tree -
  • o Tree 1
    • o Subtree 1
    • o Subtree 2
  • o Tree 2
    • o Subtree 1
    • o Subtree 2

where each "o" is a checkbox and the functions include:

• when a checkbox is checked to check, all of its child checkboxes will be checked.
• when a checkbox is checked to uncheck the checkbox, all of its child checkboxes will be unchecked.
• when a checkbox is checked to uncheck a checkbox, all of its parent checkboxes will be unchecked since it will not "select all"

What I have tried:

• ng-model and ng-changed in all trees - although not ideal.

  Select all below
   Child
   Grandchid 1
   Grandchid 2
  

  Demo

  function Ctrl($scope) {
  $scope.billing_is_shipping = true;
  
  $scope.master = true;
  $scope.child = true;
  $scope.grandchlid = true;
  
  $scope.checked = function (type) {
      switch (type) {
          case 'master':
              $scope.master = !$scope.master;
              if ($scope.master) {
  
                  $scope.child = true;
                  $scope.grandchild = true;
  
              } else {
  
                  $scope.child = false;
                  $scope.grandchild = false;
              }
              $scope.apply();
              break;
          case 'child':
              $scope.child = !$scope.child;
              if ($scope.child) {
                  $scope.grandchild = true;
  
              } else {
                  $scope.grandchild = false;
              }
              $scope.apply();
              break;
  
          case 'grandchild1':
              $scope.grandchild1 = !$scope.grandchild1;
              if(!$scope.grandchild1 || !$scope.grandchild2){
                   $scope.child = false;
                  $scope.master = false;
              }
              break;
  
      }
      console.log($scope.billing_is_shipping)
  }
  
        
  
          
          
          
        
  
      

  }

• ng-model or ng-changed only

  Demo

I've tried $ scope.apply () and without it, but I can get the first clicks to work and then everything just gives up.

Any approach or help would be greatly appreciated and thanks in advance.