AngularJS - different ways to create controllers and services, why?

Question

I keep seeing different examples of creating controllers and services in AngularJS and I\'m confused, can anyone explain to me the differences between the two approaches?

Answer 1

My preferred way of creating controllers and directives is as following:

/**
* SomeCoolModule.controller.js
*/

(function(){
'use strict';

    angular.module('app.modals.SomeCoolModule').controller('SomeCoolModuleController', SomeCoolModuleController);

    AddFlowCurveModalController.$inject =
        [
            '$scope',
            '$filter',
            '$log',
        ];

    function SomeCoolModuleController($scope, $filter, $log) {
        /* controller body goes here */
    }
})();

PS: no global namespace pollution is taking place above due to IIFE.

Answer 2

The first one will pollute the global namespace, which is not what you want in the long run.

function ExampleCtrl($scope){
    $scope.data = "some data";
}

The second one scopes the Controller to that module instance. It makes it also injectable. Better still is using the array notation (as below), since this will survive minification.

app.controller("ExampleCtrl", ['$scope', function($scope){
    $scope.data = "some data";
}]);

The difference between an (angular) service and factory seems quite small. A service wraps a factory, which uses $injector.instantiate to initialize the service.