[AngularJS] Best Practise - Factory & Services

Services:

---

 

Services are instantiated and should be class-like also and reference the this keyword, keep function style consistent with everything else.

Good:

function SomeService () {
  this.someMethod = function () {

  };
}
angular
  .module('app')
  .service('SomeService', SomeService);

 

Factory:

---

 

Factories give us a singleton module for creating service methods (such as communicating with a server over REST endpoints). Creating and returning a bound Object keeps controller bindings up to date and avoids pitfalls of binding primitive values.

Important: A "factory" is in fact a pattern/implementation, and shouldn't be part of the provider's name. All factories and services should be called "services".

Bad:

function AnotherService () {

  var someValue = '';

  var someMethod = function () {

  };
  
  return {
    someValue: someValue,
    someMethod: someMethod
  };

}
angular
  .module('app')
  .factory('AnotherService', AnotherService);

Good:

We create an Object with the same name inside the function. This can aid documentation as well for comment-generated docs.

function AnotherService () {

  var AnotherService = {};
  
  AnotherService.someValue = '';

  AnotherService.someMethod = function () {

  };
  
  return AnotherService;
}
angular
  .module('app')
  .factory('AnotherService', AnotherService);

Any bindings to primitives are kept up to date, and it makes internal module namespacing a little easier, we can easily see any private methods and variables.