Components in Angular: The Building Blocks of UI

When venturing into the realm of Angular, understanding the role of components is fundamental. Angular’s component-based architecture is a cornerstone for building dynamic and modular user interfaces. In this article, we’ll delve into the essence of Angular components, exploring their structure, lifecycle, and how they serve as the building blocks of a powerful and maintainable UI.

What Are Angular Components?

In Angular, a component is a self-contained, reusable unit that encapsulates a specific piece of functionality along with its associated HTML template and styles. Components are the building blocks of Angular applications, allowing developers to structure their code in a modular and organized manner.

Anatomy of an Angular Component:

Let’s break down the key components of an Angular component using a simple example.

1. Component Class:

The component class is the TypeScript class that contains the logic for the component. It defines properties and methods that can be used in the associated template.

Example: app.component.ts

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

  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
export class AppComponent {
  title = 'My Angular App';

In this example, we have a basic component class (AppComponent) with a property title.

2. Component Selector:

The selector is a CSS selector that identifies the HTML element in which the component will be rendered. It acts as a custom HTML tag for your component.

3. Component Template:

The template is an HTML file that defines the structure of the component. It can include Angular-specific syntax for data binding, directives, and more.

Example: app.component.html

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

Here, the template displays the value of the title property using Angular’s data binding syntax.

4. Component Styles:

The styles array in the component metadata allows you to define styles specific to the component. These styles are encapsulated and won’t affect the styles of other components.

Example: app.component.css

h1 {
  color: #4285f4;

The styles defined here will only apply to the <h1> element within the AppComponent.

Using Components in Angular:

To use a component in your Angular application, you need to do two things:

Declare the Component in a Module:Components must be declared in an Angular module. The module is a logical container that organizes the components, services, and other features of your application.

// app.module.ts
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';

  declarations: [
  // other module configurations
export class AppModule { }

Include the Component in a Template:

Use the component selector as a custom HTML tag to include it in another component’s template.

<!-- app.component.html -->

Component Lifecycle Hooks:

Angular provides a set of lifecycle hooks that allow you to tap into specific moments in the life of a component. These hooks include ngOnInit, ngOnChanges, ngOnDestroy, and more.

Example: Using ngOnInit

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

  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
export class AppComponent implements OnInit {
  title = 'My Angular App';

  ngOnInit(): void {
    console.log('Component initialized');

Learn more on LifeCycle Hooks Here


Understanding components in Angular is pivotal to becoming proficient in building robust and scalable applications. As you explore Angular further, you’ll find that the component-based architecture not only simplifies development but also promotes code reusability and maintainability. Components are indeed the building blocks that empower you to create dynamic and responsive user interfaces in Angular. Happy coding!