The Angular injector system has two types of injectors: root injector and component injectors.
1. Root Injector: The root injector is created when the Angular application is bootstrapped and is used to provide services and objects to the entire application. It acts as the top-level injector and can be accessed from anywhere in the application.
2. Component Injector: Component injectors are created for each component and are used to provide services and objects specifically for that component. A component injector is a child injector of the root injector and inherits all the services and objects provided by the root injector.
The main difference between the two types of injectors is the scope of their services and objects. The root injector provides services and objects to the entire application, while component injectors provide services and objects specific to each component.
When a component requests a service, it first checks its own component injector. If the service is not found, the component injector will ask the parent injector (the root injector) for the service. This allows components to have their own local services, while still being able to access services provided by the root injector.