Angular Components and Templates

Angular Components
Definition: Angular components are the building blocks of an Angular application. They control a portion of the user interface and manage the logic for displaying data and handling user interactions.

Structure:

Component Class: Contains the logic and data for the component. It is defined using a TypeScript class.
Component Decorator: Uses the @Component decorator to provide metadata about the component, such as its selector, template URL, and style URLs.
Metadata Properties:

• selector: The custom HTML tag that represents the component.

• templateUrl: The path to the component's HTML template.

• styleUrls: The paths to the component's CSS styles.

Example

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

@Component({
  selector: 'app-user-profile',
  templateUrl: './user-profile.component.html',
  styleUrls: ['./user-profile.component.css']
})
export class UserProfileComponent {
  user = {
    name: 'John Doe',
    email: 'john.doe@example.com'
  };

  updateUser() {
    // Logic to update user information
  }
}

Angular Templates
Definition: Templates in Angular define the view or the UI of a component. They are written in HTML and can include Angular-specific syntax for binding data and handling user events.

Role:

Data Binding: Connects the component's data to the HTML. There are four types of data binding.

• Interpolation: Display component properties in the template ({{ property }}).

• Property Binding: Bind HTML element properties to component properties ([property]="expression").

• Event Binding: Listen for and respond to user events ((event)="expression").

• Two-Way Binding: Combine property and event binding for form elements ([(ngModel)]="property").

Directives: Angular templates can use directives to manipulate the DOM. There are structural directives like *ngIf and *ngFor for conditional rendering and iteration.

Example: html

<div class="user-profile">
  <h2>{{ user.name }}</h2>
  <p>Email: {{ user.email }}</p>
  <button (click)="updateUser()">Update Profile</button>
</div>

Role in Building Angular Applications

Modularity: Components allow for modular development, making it easy to break down the application into manageable, reusable pieces.
Separation of Concerns: By separating the logic (component class) from the presentation (template), Angular promotes clean and maintainable code.
Reusability: Components can be reused throughout the application, reducing duplication and simplifying maintenance.
Testability: Components, being self-contained units, are easier to test individually.
Together, components and templates form the core of Angular applications, enabling developers to create dynamic, interactive, and maintainable user interfaces.