Two way data binding in AngularJS Directives

Question

I have been trying to define directives so I can display different \"widgets\" in a form, depending on the type of field and its parameters, which are stored in a database.

Answer 1

Here's a way to pass to a callback parameter in a directive. The controller template:

The directive:

angular.module('component')
    .directive('componentPagingSelectDirective', [
        function( ) {
            return {
                restrict: 'E',
                scope: { 
                    // using the '=' for two way doesn't work
                    pageItemLimit:  '@', // the '@' is one way from controller
                    pageChangeHandler: '&'
                },
                controller: function($scope) {   
                    // pass value from this scope to controller method. 
                    // controller method will update the var in controller scope
                    $scope.pageChangeHandler({
                        paramPulledOutOffThinAir: $scope.pageItemLimit
                    })

                }, ...

In the controller:

angular.module('...').controller(...
        $scope.pageItemLimit = 0; // initial value for controller scoped var

        // complete the data update by setting the var in controller scope 
        // to the one from the directive
        $scope.pageChangeHandler = function(paramPulledOutOffThinAir) {
            $scope.pageItemLimit = paramPulledOutOffThinAir;
        }

Note the difference in function parameters for the directive (an object with parameter as keys), template ('unwrapped' keys from the parameter object in directive), and controller definition.