What are Components in Angular?
💡 Concept Name
Angular Component – A self-contained piece of UI logic made up of a TypeScript class, HTML template, and optional styles.
📘 Quick Intro
Angular components are the core building blocks of any Angular application. They define how the UI looks and behaves and are used to structure the app into modular, reusable parts.
🧠 Analogy / Short Story
Imagine building a house with LEGO blocks—each block represents a specific room or feature. Angular components work the same way, where each component is a block that forms part of the whole application.
🔧 Technical Explanation
- 🔹 A component is defined using a
@Componentdecorator. - 🔹 Each component has a selector (HTML tag), template (view), and class (logic).
- 🔹 Angular apps start with a root component (
AppComponent) and branch into child components. - 🔹 Components can communicate using inputs, outputs, services, and lifecycle hooks.
- 🔹 Angular promotes a hierarchy of components to build complex UIs from simple parts.
🎯 Purpose & Use Case
- ✅ Divide the UI into logical, reusable parts
- ✅ Maintain separation of concerns (logic vs presentation)
- ✅ Enable component-based architecture for scalability
- ✅ Encapsulate UI behavior with modularity
💻 Real Code Example
// app.component.ts
import { Component } from '@angular/core';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
title = 'My Angular App';
}
// app.component.html
<h1>{{ title }}</h1>
❓ Interview Q&A
Q1: What is an Angular component?
A: A self-contained unit consisting of a class, HTML template, and optional CSS styles used to define UI elements.
Q2: What is the purpose of a component selector?
A: It defines the custom HTML tag used to render the component.
Q3: Can a component contain other components?
A: Yes, through component nesting.
Q4: How does data binding work in a component?
A: Angular supports interpolation, property binding, event binding, and two-way binding within templates.
Q5: What is the root component in Angular apps?
A: The AppComponent defined in the bootstrap array of AppModule.
💡 Bonus Insight
To ensure cleaner architecture, keep components focused on one concern. Use smart/dumb component patterns and leverage Angular CLI to scaffold consistent components.
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