Explain the architectural patterns MVC and MVVM. How are they implemented in Angular?

MVC (Model-View-Controller) and MVVM (Model-View-ViewModel) are architectural patterns that separate the responsibilities of application components to improve support and scalability.

• MVC divides the application into:

  • Model — data and business logic.
  • View — user interface.
  • Controller — intermediary that handles user input, updates the model, and selects the view.

• MVVM differs in that it adds a ViewModel layer, which binds the View and Model through two-way data binding:

  • Model — data and business logic.
  • View — UI.
  • ViewModel — an abstraction of the View, containing presentation logic and state, providing two-way binding with the View.

In Angular, a pattern close to MVVM is implemented:

• Component (ViewModel) — contains logic and state, binds to the template.
• Template (View) — HTML with bindings to component properties and events.
• Service (Model) — business logic and data, injected into components.

Angular uses two-way data binding (for example, with [(ngModel)]), which simplifies synchronization of state between the View and ViewModel.

Example:

@Component({
  selector: 'app-user',
  template: `
    <input [(ngModel)]="userName" />
    <p>Hello, {{ userName }}!</p>
  `
})
export class UserComponent {
  userName = '';
}

Here, UserComponent is the ViewModel, the template is the View, and the data userName is automatically synchronized between them.