The role services play in an Angular application is clear, but there can be confusion around the creation of services. This is because there are three very similar ways to create a service in Angular. We will look at each of these and why they should be used.

A service in Angular is an object that can be an authority on data (meaning it is the only source of some data). A great example is the route provider as it is the only object that provides route information. It is a singleton that all modules utilize, a way to keep data in sync between controllers, or all of these! A great example of a service that you will most likely need is $http. It makes AJAX requests for you. You can build a service that returns data from your API and you do not have to worry about creating AJAX calls in each and every controller.

Another example is the $route and $routeParams services. When you have a reference to the $route service, you can always find out what route has been matched. The $routeParams...