When all you have is a hammer, everything looks like a nail.

Angular services/factories are singletons. This has caused so many teams to forget about the joy of self contained objects that take care of themselves.

You don’t have to put all your code in static singletons and sling dummy json objects back and forth across your app.

You can enjoy real objects that make code easier to maintain!

How your code probably looks

You have a service for handling some kind of model, e.g. a Course would have a CoursesService. That service would be responsible for creating the courses and manipulating their data.

For example, you’ll use CoursesService.create(name, students, schedule). That will return some json object that you’ll then keep in your controller.

Whenever the controller would need some data about the course, it would have to use the service, passing it the object:

CoursesService.getEndDate(course)

Not only is this not very OOP-ish, it means that every binding you have in your template, e.g. to show the end date, would have $ctrl.getEndDate(course) which you’ll then implement in the controller just to proxy it to the CoursesService.

Also, having the course json object by itself isn’t usually enough, and to use it you’ll have to inject CoursesService.

Bleh.

How your code could look

Instead, we can create a real Course model that encapsulates its own data and knows how to manage by itself.

We create a service like so:

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angular.module('app').factory('Course', function() {
  return Course;

  function Course(name, students, schedule) {
    this.name = name; // Etc.

    // Put the logic here!
    this.getEndDate = ...;
  }
});

And now, all of a sudden, our code has become nicer!

You create a course using new Course(...) and then just use this instance, instead of always holding on to an object and the service.

And, for example, your templates could now directly use $ctrl.course.getEndDate() instead of proxying it using the controller.

Huzzah!