1. Architecture in Angular
Angular is a robust framework for building dynamic single-page applications (SPAs). Its architecture is based on the following core elements:
- Modules: The basic building blocks for organizing the application into cohesive blocks of functionality.
- Components: The UI elements that control views and handle user interactions.
- Templates: HTML-based views enhanced by Angular's powerful binding and directive system.
- Services: Encapsulate reusable business logic and are often used for dependency injection.
- Dependency Injection: A design pattern Angular uses to manage component dependencies and promote reusability.
2. Execution Flow in Angular
The execution flow in an Angular application follows a predictable pattern:
- Bootstrap: The Angular application starts by loading the root module, typically
AppModule
. - Component Rendering: The root component, often
AppComponent
, is rendered, and child components are recursively created as specified in the component tree. - Change Detection: Angular's change detection mechanism updates the DOM whenever component data changes.
- Event Handling: User interactions, such as clicks or form submissions, trigger event handlers defined in the components.
Here’s a simplified diagram of Angular’s execution flow:
3. Component Composition in Angular
Angular applications rely heavily on reusable and composable components. Here's how you can build effective components:
3.1 Component Basics
A component in Angular is defined using the @Component
decorator:
import { Component } from '@angular/core';
@Component({
selector: 'app-example',
template: '{{ title }}
',
styles: ['h1 { color: #007acc; }']
})
export class ExampleComponent {
title = 'Hello Angular!';
}
3.2 Component Hierarchies
Components can be composed into parent-child hierarchies. For instance, a parent component might include a child component as follows:
The child component can receive data using @Input
and communicate with the parent using @Output
.
Conclusion
Understanding the architecture, execution flow, and component composition is crucial for mastering Angular development. By leveraging these principles, developers can create scalable and maintainable applications with ease.
0 Comments