What is a dumb, or presentation, component? What are the benefits of using dumb components?

A dumb component, also known as a presentation component, is a type of component in Angular (and other frontend frameworks) that focuses solely on the presentation of data and user interface elements. It does not contain any application logic or state management, and it usually receives data via input properties and communicates changes or events back to the parent component through output properties and event emitters.

Dumb components have the following characteristics:

1. They receive data through input properties and display it.
2. They emit custom events through output properties to notify the parent component of any changes or actions.
3. They do not have direct access to or dependency on services, application state, or other external resources.
4. They are typically stateless, meaning they do not maintain their own state, although they can have internal state for managing UI behavior.
5. They usually contain a simple, self-contained template focused on presentation.

The benefits of using dumb components include:

1. Separation of concerns: Dumb components promote a clear separation between presentation and application logic, making the code easier to understand, maintain, and test.

2. Reusability: Because dumb components are self-contained and do not depend on specific application logic, they can be easily reused in different parts of an application or across multiple applications.

3. Easier testing: Dumb components are easier to test since they do not depend on external services or resources, and their behavior is mainly driven by their input and output properties.

4. Simplified maintenance: Dumb components are less prone to bugs and easier to maintain, as they focus on presentation logic and do not include complex application logic.

By using dumb components in combination with smart (or container) components, developers can create a clean, modular, and scalable architecture that clearly separates the concerns of presentation, application logic, and state management, leading to more maintainable and reusable code.