What are Angular components

Angular components are the fundamental building blocks of Angular applications. They are a key concept in Angular's architecture and are responsible for rendering views in the browser and responding to user actions. Here’s a detailed explanation of Angular components:

Definition and Structure:

1. Definition:

   • A component in Angular is a TypeScript class that interacts with the HTML view via an associated template. It encapsulates the data, logic, and behavior of a part of the user interface (UI).

2. Structure:

• Component Class (@Component): Defines the properties and methods that manage the application's data and functionality. It is decorated with @Component to provide metadata about the component, such as its selector, template, styles, and more.

  Example:
  
  

  import { Component } from '@angular/core';

  
  

  @Component({

    selector: 'app-example', // HTML tag for this component

    templateUrl: './example.component.html', // Template file path

    styleUrls: ['./example.component.css'] // Styles file(s) path

  })

  export class ExampleComponent {

    // Component logic goes here

    title = 'Example Component';

    ...

  }

• Template: An HTML view that determines what the user sees. It includes Angular directives and binding markup ({{ }}, [ ], ( )) to display data and respond to user events.

  Example (example.component.html):
  
  

  <h1>{{ title }}</h1>

  <button (click)="onClick()">Click me!</button>

• Styles: Optional CSS styles that apply specifically to the component's view.

  Example (example.component.css):
  
  

  h1 {

    color: blue;

  }

Responsibilities:

1. Rendering UI:

   • Components are responsible for rendering UI elements based on the data and logic defined in the component class and template.

2. Handling User Input:

   • Components respond to user actions such as clicks, keystrokes, etc., through event binding ((event)="handler()") and other input mechanisms.

3. Data Binding:

   • Components facilitate data binding between the component class (data model) and the template (view), ensuring synchronization of data and UI state.

4. Lifecycle Hooks:

   • Components have lifecycle hooks (ngOnInit, ngOnChanges, ngOnDestroy, etc.) that allow developers to tap into key moments in the component's lifecycle and perform actions.

Component Communication:

1. Input/Output Properties:

   • Components can communicate with other components via Input and Output properties (@Input(), @Output()), enabling parent-child and sibling component communication.

2. Services:

   • Components can use Angular services to fetch data from servers, encapsulate business logic, and share data across components.

Benefits:

• Modularity: Components promote modularity and reusability by encapsulating specific UI parts and behavior.
• Separation of Concerns: Components separate the UI representation (template) from the application logic (component class), enhancing maintainability.
• Encapsulation: Each component operates independently, with its own view and data, minimizing conflicts and making it easier to debug and test.

In summary, Angular components are the cornerstone of Angular applications, encapsulating the UI and logic of specific parts of the application. They enable structured development, maintainability, and effective communication within the application architecture.