In Angular, decorators are functions that allow a class, method, or property to be modified or decorated without modifying the source code. Decorators are invoked with a prefixed @ symbol, followed by the class, method, or property that is being decorated. The purpose of Angular decorators is to store metadata about a class, method, or property, which tells Angular that a particular class is a component, directive, pipe, service, or module. There are four types of decorators in Angular:

• Class decorators: These are the top-level decorators that define the purpose for the classes. They provide information to Angular that a particular class is a component or module.

• Property decorators: These are used to decorate specific properties within the classes. They allow us to decorate some properties within our classes, such as InputBinding.

• Method decorators: These are used to decorate specific methods within the classes. They allow us to modify the behavior of the methods.

• Parameter decorators: These are used to decorate specific parameters within the methods. They allow us to modify the behavior of the parameters.

Decorators are a core concept when developing with Angular, and they allow developers to add functionality to classes, methods, and properties without modifying the source code.