I'm new to AngularJS. I'm currently looking at the services. Some of these services look like the replace functions already available in JavaScript. For instance, the $timeout service. Why does AngularJS have these services? Is there a technical reason? Are there any advantages to this approach? I just don't understand the need for using these services.
Thank you for any help.
A service is a function or an object, with a set of methods, that could be used by several components (controllers, directives, filters, other services) of your application.
The main advantage that "wrapping" services like $timeout or $window have over their global functions equivalent is that they're injected by Angular, and can thus be mocked in unit tests, i.e. replaced by fake implementations.
Read the chapter about dependency injection in the angular documentation. Regarding the $timeout service in particular, its documentation explains what it does in addition to the native setTimeout() function.