The Complete Guide to Angular

Introduction

Angular remains one of the most powerful and widely used frameworks for building dynamic web applications. Developed by Google, Angular is a TypeScript-based front-end framework that provides a structured way to create scalable and maintainable applications.

In this comprehensive guide, we’ll explore everything you need to know about Angular in 2025, including its core features, setup, best practices, optimization techniques, and real-world examples.

What is Angular?

Angular is an open-source front-end framework designed for building single-page applications (SPAs) and complex web interfaces. It follows a component-based architecture and is known for its high performance and flexibility.

Key Features of Angular

• Component-Based Architecture—Modular development with reusable components.

• Two-Way Data Binding—Synchronises data between the model and view.

• Dependency injection—enhances modularity and scalability.

• Directives—Custom attributes that extend HTML capabilities.

• Routing—efficient navigation across different views.

• RxJS and Observables—Enables reactive programming and async data handling.

• State Management—Uses NgRx for efficient application of state management.

Setting Up an Angular Project

To get started with Angular, install Angular CLI (Command Line Interface):

# Install Angular CLI globally
npm install -g @angular/cli

# Create a new Angular project
ng new my-angular-app

# Navigate to the project directory
cd my-angular-app

# Run the development server
ng serve --open

This will create a new Angular project and start a local development server.

Understanding Angular Components

Components are the building blocks of Angular applications. Each component consists of:

• Template (HTML): defines the UI structure.

• Styles (CSS/SCSS)—styles the component.

• Class (TypeScript): Contains logic and data.

Creating a Component

# Generate a new component
ng generate component my-component

Component Example

my-component.component.ts

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

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent {
  message: string = 'Hello, Angular!';
}

my-component.component.html

<div>
  <h2>{{ message }}</h2>
</div>

Angular Services and Dependency Injection

Services in Angular are used to share logic across components. They are injected using Angular's Dependency Injection (DI) system.

Creating a Service

ng generate service my-service

Fetching Data with HTTP Client

my-service.service.ts

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable({
  providedIn: 'root'
})
export class MyService {
  private apiUrl = 'https://api.example.com/data';

  constructor(private http: HttpClient) {}

  getData(): Observable<any> {
    return this.http.get(this.apiUrl);
  }
}

Routing in Angular

Angular provides a powerful router module for navigation between views.

Configuring Routes

app-routing.module.ts

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { HomeComponent } from './home/home.component';
import { AboutComponent } from './about/about.component';

const routes: Routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule {}

Adding Router Links in Templates

<nav>
  <a routerLink="/">Home</a>
  <a routerLink="/about">About</a>
</nav>
<router-outlet></router-outlet>

State Management with NgRx

NgRx is used for managing the application state efficiently.

Installing NgRx

npm install @ngrx/store @ngrx/effects

Defining a State and Reducer

import { createReducer, on } from '@ngrx/store';
import { increment, decrement } from './counter.actions';

export const initialState = 0;

export const counterReducer = createReducer(
  initialState,
  on(increment, (state) => state + 1),
  on(decrement, (state) => state - 1)
);

Optimizing Angular Applications

Lazy Loading Modules

Load feature modules only when needed to reduce initial load time.

const routes: Routes = [
  { path: 'feature', loadChildren: () => import('./feature/feature.module').then(m => m.FeatureModule) }
];

OnPush Change Detection

Improves rendering performance.

@Component({
  selector: 'app-optimized',
  templateUrl: './optimized.component.html',
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class OptimizedComponent {}

Minimize Bundle Size

Use Ahead-of-Time (AOT) Compilation and tree shaking.

ng build --prod --aot

Use TrackBy with ngFor

Prevents unnecessary DOM updates.

<div *ngFor="let item of items; trackBy: trackById">
  {{ item.name }}
</div>

trackById(index: number, item: any) {
  return item.id;
}

Conclusion

Angular continues to evolve as one of the most powerful frameworks for web development in 2025. By following best practices, leveraging modular architecture, and optimising performance, you can build scalable and high-quality applications.

Are you using Angular for your projects? Share your experiences in the comments!