使用与 providedIn 相同的服务：root 作为单例和组件的提供者与服务

Question

I would like to know what happens if the following criteria happen.

Created a service as single-ton with providedIn property as root. So that it will be available to the application globally. At the same time, providers meta data in component or module set to the created service. Can any one tell me what is the effect on this situation?

Answer 1

To get more about Singletons you need to refer to official documentation . Answering your question its quite simple. Singletons are globals for entire application and share the same data. For example, you have a service which adds a script to the head or authentication service which holds global auth status - you need to ensure that they have only one instance across entire application.