directive2directive.js

var app = angular.module('superApp', []);

app.directive('superhero', function() {
  return {
    restrict: 'E',
    scope: {},

    controller: function($scope) {
      $scope.abilities = [];

      this.addStrength = function() {
        $scope.abilities.push('strength'); 
      } 

      this.addSpeed = function() {
        $scope.abilities.push('speed'); 
      }

      this.addFlight = function() {
        $scope.abilities.push('flight'); 
      }
    },

    link: function(scope, element) {
      element.addClass('button');
      element.bind('mouseenter', function() {
        console.log(scope.abilities) 
      });
    }
  }
});

app.directive('strength', function() {
  return {
    require: "superhero",
    link: function(scope, element, attrs, superheroCtrl) {
      superheroCtrl.addStrength(); 
    }
  }
})
app.directive('speed', function() {
  return {
    require: "superhero",
    link: function(scope, element, attrs, superheroCtrl) {
      superheroCtrl.addSpeed(); 
    }
  }
})
app.directive('flight', function() {
  return {
    require: "superhero",
    link: function(scope, element, attrs, superheroCtrl) {
      superheroCtrl.addFlight(); 
    }
  }
})