AngularJS Custom Directive Two Way Binding

Question

If I have an AngularJS directive without a template and I want it to set a property on the current scope, what is the best way to do it?

For example, a directive tha

Answer 1

I'm surprised no one has mentioned ng-model, the default directive for doing two-data binding. Maybe it's not so well known, but the linking function has a fourth parameter:

angular.module('directive-binding', [])
  .directive('twoway', 
      function() {
        return {
          require: '?ngModel',
          link: function(scope, elem, attrs, ngModel) {
            elem.on('click', function() {
              var counter = ngModel.$viewValue ? ngModel.$viewValue : 0
              ngModel.$setViewValue(++counter);
              scope.$apply();
            });
          }
        };
      }
    );

On your view

Click Me
Click Count: {{ counter }}

The fourth parameter is an API for the ngModelController, which has many uses for handling (parsing and formatting, for instance) and sharing data between a directive and a scope.

Here's the updated Plunker.