Angular consists of several building blocks that work together to create robust web applications. Here are the key building blocks of Angular:
1. Components: Components are the fundamental building blocks of an Angular application. They encapsulate the application's UI and logic, representing different parts of the user interface. Components consist of a template (HTML markup), styles (CSS), and a TypeScript class that defines the component's behavior.
2. Templates: Templates define the structure and layout of the UI for a component. They use HTML markup combined with Angular's template syntax, which includes directives, data binding, and other features to manipulate and display data dynamically.
3. Directives: Directives are instructions given to the HTML markup that modify its behavior or appearance. Angular provides built-in directives like `ngIf`, `ngFor`, and `ngSwitch` for conditional rendering, iteration, and switching logic. Additionally, Angular allows you to create custom directives to extend the functionality of your application.
4. Services: Services provide a way to organize and share common functionality across multiple components. Services handle tasks such as data retrieval from APIs, data manipulation, authentication, logging, and more. They are typically injected into components or other services using dependency injection.
5. Modules: Modules are containers that group related components, directives, services, and other code into cohesive units. Angular applications are composed of multiple modules, including the root module (`AppModule`) and feature modules. Modules help with organization, encapsulation, and manage dependencies within an application.
6. Dependency Injection (DI): Dependency Injection is a design pattern and mechanism used in Angular to manage the dependencies of components and services. It allows you to inject dependencies into a class without explicitly creating or managing those dependencies yourself. Angular's DI system provides a way to declare, provide, and inject dependencies through constructor parameters or property injection.
7. Routing: Angular's Router module allows you to implement client-side navigation and define routes for different components. It provides features like route configuration, parameter passing, route guards for authentication and authorization, lazy loading of modules, and more. Routing enables the creation of single-page applications (SPAs) with multiple views.
8. Forms: Angular provides powerful form-handling capabilities, including both template-driven forms and reactive forms. Forms allow you to capture user input, perform validation, and handle form submission. Angular forms provide features like two-way data binding, form validation, form controls, form groups, and form builders.
9. Pipes: Pipes are a way to transform and format data in templates. They allow you to apply filters, manipulate dates, format numbers, convert text case, and more. Angular provides built-in pipes like `date`, `uppercase`, `lowercase`, and `currency`, and you can create custom pipes for specific transformation needs.
These building blocks work together to create a structured and modular Angular application. Components define the UI, templates render the UI, services provide common functionality, modules organize the application, DI manages dependencies, routing enables navigation, forms handle user input, and pipes transform data for display. Understanding and effectively utilizing these building blocks is essential for developing Angular applications.