[javascript] Share data between AngularJS controllers

There are multiple ways to do this.

1. Events - already explained well.

2. ui router - explained above.

3. Service - with update method displayed above
4. BAD - Watching for changes.
5. Another parent child approach rather than emit and brodcast -

*

<superhero flight speed strength> Superman is here! </superhero>
<superhero speed> Flash is here! </superhero>

*

app.directive('superhero', function(){
    return {
        restrict: 'E',
        scope:{}, // IMPORTANT - to make the scope isolated else we will pollute it in case of a multiple components.
        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, attrs){
            element.addClass('button');
            element.on('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();
        }
    }
});