The HttpClient module in Angular has a feature called an HTTP Interceptor that enables developers to examine and modify HTTP requests and answers globally before application logic handles them.  Tasks including adding authorization tokens to headers, logging, resolving failures, and altering requests and answers are all frequently performed by interceptors.

Key Features of HTTP Interceptors

• Middleware for HTTP Requests and Responses: Interceptors sit between the application and the backend, processing all HTTP requests and responses.
• Global Scope: Once an interceptor is configured, it applies to all HTTP requests and responses in the application.
• Chaining: Multiple interceptors can be implemented, and they are executed in the order they are provided.

Benefits of HTTP Interceptors
Following are some of the key benefits of using HTTP Interceptors in Angular.

• Testability and reusability: Interceptors are easy to test in isolation, allowing you to ensure that each interceptor behaves correctly
• Centralized code for cross-cutting concerns: HTTP Interceptors allow you to define logic for common tasks, such as authentication, logging, error handling, or adding headers, in a centralized location.
• Global application-level modifications: Interceptors operate globally, intercepting all HTTP requests and responses made by the Angular application. This means you can apply changes or perform actions consistently across multiple API calls without having to modify each individual request or response manually.
• Error handling and logging: Interceptors can be utilized to handle errors globally, providing a consistent approach to error reporting and handling throughout the application.
• Caching and request/response manipulation: HTTP Interceptors can be leveraged to implement caching mechanisms, reducing redundant requests and optimizing the application’s performance.
• Separation of concerns: By using HTTP Interceptors, you can keep concerns related to data fetching and communication (HTTP) separate from the business logic of your components and services.
• Security and authentication: Interceptors are commonly used to add authorization headers or authentication tokens to outgoing requests. This ensures that the user’s authentication status is automatically included in API calls without the need to explicitly set headers in every request.
• Easy integration with third-party libraries: Interceptors can be used to integrate with third-party libraries or APIs seamlessly. For example, you can apply a specific format to API responses that are expected by a charting library or a data visualization tool.

Logging Interceptor

import { Injectable } from '@angular/core';
import {
  HttpEvent,
  HttpInterceptor,
  HttpHandler,
  HttpRequest,
  HttpResponse,
} from '@angular/common/http';
import { Observable, tap } from 'rxjs';

@Injectable()
export class LoggingInterceptor implements HttpInterceptor {
  constructor() {}

  intercept(
    request: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {
    console.log('Outgoing HTTP request', request);
    return next.handle(request).pipe(
      tap((event: HttpEvent<any>) => {
        console.log('Incoming HTTP response', event);
      })
    );
  }
}

Provide an interceptor in the app module.
import { LoggingInterceptor } from './interceptors/logging.interceptor';

providers: [
  {
    provide: HTTP_INTERCEPTORS,
    useClass: LoggingInterceptor,
    multi: true,
  },
];

Adding Headers to Requests
import { Injectable } from '@angular/core';
import {
  HttpRequest,
  HttpHandler,
  HttpEvent,
  HttpInterceptor
} from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable()
export class HeadersInterceptor implements HttpInterceptor {
  constructor() {}

  intercept(
    request: HttpRequest<unknown>,
    next: HttpHandler
  ): Observable<HttpEvent<unknown>> {
    console.log(request);
    const GUID = 'f4189b26-01af-432c-bcd8-cb4bc7e90980';
    const modifiedRequest = request.clone({
      setHeaders: {
        GUID,
      },
    });
    return next.handle(modifiedRequest);
  }
}

Provide an interceptor in the app module.
import { HeadersInterceptor  } from './interceptors/headers.interceptor'

providers: [
    {
      provide: HTTP_INTERCEPTORS, useClass: HeadersInterceptor, multi: true
    }
  ]

Error Handling Interceptor
import { Injectable } from '@angular/core';
import {
  HttpRequest,
  HttpHandler,
  HttpEvent,
  HttpInterceptor,
  HttpErrorResponse,
} from '@angular/common/http';
import { Observable, catchError, throwError } from 'rxjs';

@Injectable()
export class ErrorInterceptor implements HttpInterceptor {
  constructor() {}

  intercept(
    request: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {
    return next.handle(request).pipe(
      catchError((error: HttpErrorResponse) => {
        // Handle the error here
        console.error('error occurred:', error);
        // throw error as per requirement
        return throwError(error);
      })
    );
  }
}

Provide an interceptor in the app module.
import { ErrorInterceptor } from './interceptors/error.interceptor';

  providers: [
    {
      provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true
    }
  ]

Authentication Interceptor
CLI command: ng generate interceptor auth.
import { Injectable } from '@angular/core';
import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';
import { Observable } from 'rxjs';
import { AuthService } from './auth.service'; // Service to get the token

@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  constructor(private authService: AuthService) {}

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // Get the token from the AuthService
    const authToken = this.authService.getToken();

    // Clone the request and add the Authorization header
    const authReq = authToken
      ? req.clone({
          headers: req.headers.set('Authorization', `Bearer ${authToken}`),
        })
      : req;

    return next.handle(authReq);
  }
}

Create the AuthService
import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class AuthService {
  private token: string | null = null;

  // Simulate storing and retrieving the token
  setToken(token: string): void {
    this.token = token;
  }

  getToken(): string | null {
    return this.token;
  }

  clearToken(): void {
    this.token = null;
  }
}

Register the Interceptor
import { NgModule } from '@angular/core';
import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { AuthInterceptor } from './auth.interceptor';

@NgModule({
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: AuthInterceptor,
      multi: true, // Allow multiple interceptors
    },
  ],
})
export class AppModule {}

Handle Token Expiration
import { Router } from '@angular/router';
import { catchError } from 'rxjs/operators';
import { throwError } from 'rxjs';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  constructor(private authService: AuthService, private router: Router) {}

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const authToken = this.authService.getToken();

    const authReq = authToken
      ? req.clone({
          headers: req.headers.set('Authorization', `Bearer ${authToken}`),
        })
      : req;

    return next.handle(authReq).pipe(
      catchError((error) => {
        if (error.status === 401) {
          // Redirect to login page on unauthorized response
          this.authService.clearToken();
          this.router.navigate(['/login']);
        }
        return throwError(error);
      })
    );
  }
}

With this post, we'll use Recharts with an Angular frontend and a Node.js backend to build a dashboard with stunning charts.

To concentrate on the UI for the time being, we will use hardcoded data. Real data can be connected later.

1.1 Install Angular CLI
Make sure you have Node.js installed. Then install Angular CLI globally:
npm install -g @angular/cli

1.2 Create a New Angular Project
ng new dashboard-app
cd dashboard-app

1.3  Create the Dashboard Component
We’ll create a DashboardComponent with hardcoded data for revenue, user activity, and sales. The component uses Chart.js to render three charts: a line chart for revenue, a line chart for user activity, and a bar chart for sales by category.

Here’s the code for dashboard.component.ts:
import { Component, OnInit } from '@angular/core';
import { CommonModule } from '@angular/common';
import { Chart } from 'chart.js/auto';

interface ChartData {
  month: string;
  revenue: number;
}

@Component({
  selector: 'app-dashboard',
  standalone: true,
  imports: [CommonModule],
  template: `
    <div class="dashboard-container p-8">
      <h1 class="text-4xl font-bold mb-8">Dashboard</h1>

      <!-- Stats Grid -->
      <div class="stats-grid mb-8">
        <div class="stat-card" *ngFor="let stat of stats">
          <div class="stat-header">
            <span class="stat-title">{{stat.title}}</span>
            <i class="stat-icon" [class]="stat.icon"></i>
          </div>
          <div class="stat-value">{{stat.value}}</div>
        </div>
      </div>

      <!-- Charts -->
      <div class="charts-grid mb-8">
        <div class="chart-container">
          <canvas id="revenueChart"></canvas>
        </div>
        <div class="chart-container">
          <canvas id="userActivityChart"></canvas>
        </div>
      </div>

      <div class="chart-container">
        <canvas id="salesChart"></canvas>
      </div>
    </div>
  `,
  styles: [`
    .dashboard-container {
      max-width: 1400px;
      margin: 0 auto;
    }

    .stats-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
      gap: 1rem;
    }

    .stat-card {
      background: white;
      padding: 1.5rem;
      border-radius: 8px;
      box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }

    .stat-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 0.5rem;
    }

    .stat-title {
      font-size: 0.875rem;
      color: #64748b;
    }

    .stat-value {
      font-size: 1.5rem;
      font-weight: bold;
      color: #1e293b;
    }

    .charts-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
      gap: 1rem;
    }

    .chart-container {
      background: white;
      padding: 1rem;
      border-radius: 8px;
      box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }
  `]
})
export class DashboardComponent implements OnInit {
  stats = [
    { title: 'Total Revenue', value: '$443,000', icon: 'bi bi-currency-dollar' },
    { title: 'Average Order', value: '$245', icon: 'bi bi-credit-card' },
    { title: 'Total Customers', value: '12.5K', icon: 'bi bi-people' },
    { title: 'Total Orders', value: '8.2K', icon: 'bi bi-cart' }
  ];

  revenueData = {
    labels: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
    datasets: [{
      label: 'Revenue',
      data: [24000, 26000, 32000, 28000, 35000, 42000, 39000, 45000, 48000, 52000, 49000, 55000],
      borderColor: 'rgb(75, 192, 192)',
      tension: 0.1
    }]
  };

  userActivityData = {
    labels: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'],
    datasets: [
      {
        label: 'Active Users',
        data: [3200, 3800, 4200, 3900, 3600, 2900, 2800],
        borderColor: 'rgb(75, 192, 192)',
        tension: 0.1
      },
      {
        label: 'New Users',
        data: [1400, 1600, 1800, 1500, 1300, 1000, 900],
        borderColor: 'rgb(255, 99, 132)',
        tension: 0.1
      }
    ]
  };

  salesData = {
    labels: ['Electronics', 'Clothing', 'Books', 'Home', 'Sports'],
    datasets: [{
      label: 'Sales by Category',
      data: [42000, 28000, 15000, 22000, 18000],
      backgroundColor: [
        'rgba(255, 99, 132, 0.5)',
        'rgba(54, 162, 235, 0.5)',
        'rgba(255, 206, 86, 0.5)',
        'rgba(75, 192, 192, 0.5)',
        'rgba(153, 102, 255, 0.5)'
      ]
    }]
  };

  constructor() {}

  ngOnInit(): void {
    this.createCharts();
  }

  private createCharts(): void {
    // Revenue Chart
    new Chart('revenueChart', {
      type: 'line',
      data: this.revenueData,
      options: {
        responsive: true,
        maintainAspectRatio: false
      }
    });

    // User Activity Chart
    new Chart('userActivityChart', {
      type: 'line',
      data: this.userActivityData,
      options: {
        responsive: true,
        maintainAspectRatio: false
      }
    });

    // Sales Chart
    new Chart('salesChart', {
      type: 'bar',
      data: this.salesData,
      options: {
        responsive: true,
        maintainAspectRatio: false
      }
    });
  }
}

Code in app.component.ts
import { Component } from '@angular/core';
import { RouterOutlet } from '@angular/router';
import { CommonModule } from '@angular/common';

@Component({
  selector: 'app-root',
  standalone: true,
  imports: [RouterOutlet, CommonModule],
  template: `
    <div class="app-container">
      <router-outlet></router-outlet>
    </div>
  `,
  styles: [`
    .app-container {
      min-height: 100vh;
      background-color: #f8f9fa;
      padding: 1rem;
    }
  `]
})
export class AppComponent {
  title = 'dashboard';
}

Code for not-found.component.ts
import { Component } from '@angular/core';
import { CommonModule } from '@angular/common';

@Component({
  selector: 'app-not-found',
  standalone: true,
  imports: [CommonModule],
  template: `
    <div class="not-found-container">
      <div class="error-card">
        <div class="error-header">
          <i class="bi bi-exclamation-circle text-red-500"></i>
          <h1>404 Page Not Found</h1>
        </div>
        <p>The page you're looking for doesn't exist.</p>
      </div>
    </div>
  `,
  styles: [`
    .not-found-container {
      min-height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      background-color: #f8f9fa;
      padding: 1rem;
    }

    .error-card {
      background: white;
      padding: 2rem;
      border-radius: 8px;
      box-shadow: 0 2px 4px rgba(0,0,0,0.1);
      max-width: 400px;
      width: 100%;
    }

    .error-header {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      margin-bottom: 1rem;
    }

    h1 {
      font-size: 1.5rem;
      font-weight: bold;
      color: #1e293b;
    }

    p {
      color: #64748b;
    }
  `]
})
export class NotFoundComponent {}

import { Routes } from '@angular/router';

export const routes: Routes = [
  {
    path: '',
    loadComponent: () => import('./dashboard/dashboard.component')
      .then(m => m.DashboardComponent)
  },
  {
    path: '**',
    loadComponent: () => import('./not-found/not-found.component')
      .then(m => m.NotFoundComponent)
  }
];

Server Side code - index.js
import express, { type Request, Response, NextFunction } from "express";
import { registerRoutes } from "./routes";
import path from "path";
import { fileURLToPath } from "url";
import { dirname } from "path";

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

const app = express();
app.use(express.json());
app.use(express.urlencoded({ extended: false }));

// Logging middleware
app.use((req, res, next) => {
  const start = Date.now();
  const path = req.path;
  let capturedJsonResponse: Record<string, any> | undefined = undefined;

  const originalResJson = res.json;
  res.json = function (bodyJson, ...args) {
    capturedJsonResponse = bodyJson;
    return originalResJson.apply(res, [bodyJson, ...args]);
  };

  res.on("finish", () => {
    const duration = Date.now() - start;
    if (path.startsWith("/api")) {
      let logLine = `${req.method} ${path} ${res.statusCode} in ${duration}ms`;
      if (capturedJsonResponse) {
        logLine += ` :: ${JSON.stringify(capturedJsonResponse)}`;
      }

      if (logLine.length > 80) {
        logLine = logLine.slice(0, 79) + "…";
      }

      console.log(`${new Date().toLocaleTimeString()} [express] ${logLine}`);
    }
  });

  next();
});

(async () => {
  const server = await registerRoutes(app);

  app.use((err: any, _req: Request, res: Response, _next: NextFunction) => {
    const status = err.status || err.statusCode || 500;
    const message = err.message || "Internal Server Error";
    res.status(status).json({ message });
    throw err;
  });

  // Serve static files from the Angular build output directory
  const distPath = path.resolve(__dirname, "..", "dist", "public");
  app.use(express.static(distPath));

  // Always return index.html for any non-API routes (Angular routing)
  app.get("*", (_req, res) => {
    res.sendFile(path.join(distPath, "index.html"));
  });

  const port = 5000;
  server.listen({
    port,
    host: "0.0.0.0",
    reusePort: true,
  }, () => {
    console.log(`${new Date().toLocaleTimeString()} [express] serving on port ${port}`);
  });
})();

angular.json file
{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "dashboard": {
      "projectType": "application",
      "schematics": {},
      "root": "client",
      "sourceRoot": "client/src",
      "prefix": "app",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/public",
            "index": "client/src/index.html",
            "main": "client/src/main.ts",
            "polyfills": ["zone.js"],
            "tsConfig": "tsconfig.json",
            "assets": [
              "client/src/favicon.ico",
              "client/src/assets"
            ],
            "styles": [
              "client/src/styles.css",
              "node_modules/bootstrap-icons/font/bootstrap-icons.css"
            ],
            "scripts": []
          },
          "configurations": {
            "production": {
              "budgets": [
                {
                  "type": "initial",
                  "maximumWarning": "500kb",
                  "maximumError": "1mb"
                },
                {
                  "type": "anyComponentStyle",
                  "maximumWarning": "2kb",
                  "maximumError": "4kb"
                }
              ],
              "fileReplacements": [
                {
                  "replace": "client/src/environments/environment.ts",
                  "with": "client/src/environments/environment.prod.ts"
                }
              ],
              "outputHashing": "all"
            },
            "development": {
              "buildOptimizer": false,
              "optimization": false,
              "vendorChunk": true,
              "extractLicenses": false,
              "sourceMap": true,
              "namedChunks": true
            }
          },
          "defaultConfiguration": "production"
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "configurations": {
            "production": {
              "browserTarget": "dashboard:build:production"
            },
            "development": {
              "browserTarget": "dashboard:build:development"
            }
          },
          "defaultConfiguration": "development"
        }
      }
    }
  }
}

This post showed how to use Angular and Node.js to create an eye-catching dashboard. We produced adaptable and interactive charts that make data come to life by utilizing Chart.js. This stack is perfect for creating scalable apps because of Angular's modular design and Node.js's speed. Additional charts, authentication, and the integration of real-time data sources are possible future enhancements. You may design dashboards of expert quality that meet your demands with this base.

In this comprehensive guide, we'll build a modern User Management System using Angular. This application showcases several advanced features including theme switching, undo/redo functionality, and robust data management.

Table of Contents

Project Overview

• Architecture and Design
• Core Features Implementation
• Services Implementation
• Component Development
• Advanced Features
• Best Practices and Tips

Project Overview
Our User Management System includes the following features.

• Modern, responsive design with light/dark theme support
• Interactive data grid with in-place editing
• Complete CRUD operations with validation
• Undo/Redo functionality
• Data export capabilities (Excel, PDF, PNG)
• Loading placeholders
• Enhanced user experience with tooltips
• Form validation with error messages
• Duplicate entry prevention
• Confirmation dialogs
• Local storage persistence
• Reusable components

Architecture and Design
Project Structure
src/
├── app/
│   ├── components/
│   │   ├── user-grid/
│   │   └── shared/
│   ├── services/
│   │   ├── user.service.ts
│   │   ├── theme.service.ts
│   │   └── data.service.ts
│   └── models/
│       └── user.model.ts

Core Models
// user.model.ts
export interface User {
    id?: number;
    name: string;
    userName: string;
    email: string;
    phone: string;
    website: string;
}
export interface UserState {
    users: User[];
    undoStack: User[][];
    redoStack: User[][];
}

Core Features Implementation
Theme Service: The theme service manages application-wide theme switching.
    @Injectable({
      providedIn: 'root'
    })
    export class ThemeService {
      private isDarkTheme = new BehaviorSubject<boolean>(false);
      isDarkTheme$ = this.isDarkTheme.asObservable();
      constructor() {
        const savedTheme = localStorage.getItem('theme');
        if (savedTheme) {
          this.setDarkTheme(savedTheme === 'dark');
        }
      }
      setDarkTheme(isDark: boolean) {
        this.isDarkTheme.next(isDark);
        localStorage.setItem('theme', isDark ? 'dark' : 'light');
        document.body.classList.toggle('dark-theme', isDark);
      }
    }

User Service: The User Service handles all data operations with undo/redo support.
@Injectable({
  providedIn: 'root'
})
export class UserService {
  private readonly STORAGE_KEY = 'user_data';

  private state: UserState = {
    users: [],
    undoStack: [],
    redoStack: []
  };

  private usersSubject = new BehaviorSubject<User[]>([]);
  users$ = this.usersSubject.asObservable();

  // CRUD Operations with Undo/Redo Support
  addUser(user: User): boolean {
    if (this.isDuplicate(user)) return false;

    this.pushToUndoStack();
    user.id = this.getNextId();
    this.state.users.push(user);
    this.updateState();

    return true;
  }

  // Additional methods for update, delete, undo, redo
}

Data Grid Component: The main grid component implements the user interface.
@Component({
  selector: 'app-user-grid',
  template: `
    <div class="user-grid-container" [class.dark-theme]="isDarkTheme$ | async">
      <div class="header">
        <h2>User Management</h2>
        <div class="actions">
          <app-button (click)="addNewUser()">Add User</app-button>
          <app-button (click)="toggleTheme()">Toggle Theme</app-button>
        </div>
      </div>
      <!-- Grid implementation -->
    </div>
  `
})
export class UserGridComponent implements OnInit {
  users$ = this.userService.getUsers();
  isDarkTheme$ = this.themeService.isDarkTheme$;

  constructor(
    private userService: UserService,
    private themeService: ThemeService
  ) {}
}

Advanced Features
Export Functionality
export class ExportService {
  exportToExcel(data: User[]) {
    const worksheet = XLSX.utils.json_to_sheet(data);
    const workbook = XLSX.utils.book_new();
    XLSX.utils.book_append_sheet(workbook, worksheet, 'Users');
    XLSX.writeFile(workbook, 'users.xlsx');
  }
  // Similar methods for PDF and PNG export
}

Loading Placeholders
<ng-container *ngIf="loading$ | async; else userGrid">
  <div class="placeholder-grid">
    <div class="placeholder-row" *ngFor="let i of [1, 2, 3, 4, 5]">
      <!-- Placeholder content -->
    </div>
  </div>
</ng-container>

Form Validation
export class UserFormComponent {
  userForm = this.fb.group({
    name: ['', [Validators.required, Validators.minLength(2)]],
    email: ['', [Validators.required, Validators.email]],
    userName: ['', [Validators.required, Validators.pattern('[a-zA-Z0-9_-]*')]],
    // Additional form controls
  });
}
Tips

• State Management
  • Use BehaviorSubject for reactive state management
  • Implement undo/redo using stack data structures
  • Persist state changes to localStorage
• Performance Optimization
  • Use OnPush change detection strategy
  • Implement trackBy functions for ngFor loops
  • Lazy load features when possible
• Error Handling
  • Implement comprehensive error handling
  • Use toast notifications for user feedback
  • Log errors appropriately

This User Management System demonstrates several Angular best practices and advanced features. Key takeaways include.

• Proper service architecture for state management
• Implementing complex features like undo/redo
• Creating reusable components
• Managing application themes
• Handling data persistence
• Form validation and error handling

Have you ever wondered how Angular apps seem to handle intricate dependencies and logic with ease? The magic that happens behind the scenes with services and dependency injection (DI) is frequently the key. These Angular features are the unsung heroes that drive the scalability and maintainability of your app, despite the fact that they might sound like catchphrases.

In-depth discussions of services, their creation and usage, and how Angular's DI system may help you manage dependencies more efficiently will all be covered in this article. Consider this your backstage ticket to learning the architecture of Angular, where we will unravel the intricacies of DI and demonstrate how to use it to improve the modularity, testability, and—above all—efficiency of your application.

Let's get started and discover Angular's services and DI capability!

Services
For an easier understanding, we will use the analogy of a remote control.
You do not need to go up to the TV to change channels, adjust the volume, or turn it on and off. You just use the remote (service), which is always there, to perform these actions from a distance.

In Angular, services are like this remote. Components don’t need to directly handle or interact with complex logic or data—they just "press a button" (call a service method), and the service handles the rest. It simplifies things and keeps everything within easy reach.

Another important aspect is reusability. With a universal remote control, you can control multiple devices. Instead of having to adjust each device manually or have a separate remote for each, the universal remote lets you control all these devices with just one tool.

In Angular, a service is a reusable piece of code that you can "call" from any component in your app. Whether it is fetching data, performing a calculation, or handling complex logic, you don’t have to rewrite the same functionality in multiple components. You simply "press the button" (call the service) wherever it is needed, and the service does the job, ensuring that your app remains clean, DRY (Don’t Repeat Yourself), and easy to maintain.

Services maximize reusability and provide a better code structure for your project.

When to use a service?
In Angular, a service should be used when you need to:

• Share data or logic across components: Services provide a central place where data or business logic can be shared across multiple components, so you don't have to duplicate code in each component.
• Encapsulate business logic: If you have complex logic or operations that don’t belong directly in a component, putting them in service makes your code cleaner and more maintainable.
• Make HTTP requests: Services are commonly used for interacting with back-end APIs. Instead of having HTTP requests directly inside components, you use services to handle all the communication with the server.
• Manage state: Services can manage the state of your application, like keeping track of user authentication, settings, or preferences, and can keep this state consistent across components.
• Improve testability: By separating business logic into services, you can more easily write unit tests for that logic. It also allows mocking or stubbing services in tests to isolate components.

Creating a service

• Create your angular project
• Create the service you need using the following command

ng generate service <<name of the service>>

If you need to create the service in a specific file, you can modify the command slightly as follows:
ng generate service <<folder-path/name_of_the_service>>

For our demo, we will create our service in the ‘my-services-folder’ folder and call it ‘my-first-service’. We will use this command: ng generate service my-services-folder/my-first-service

Once the command is successfully executed, you will see the following:

The project will include the following:

When you open the service.ts file, you will see the following file already created for you:

You can start writing your functions under the constructor [as from line 9].

Note. A common practice is to have API calls in services. For the sake of simplicity, a function returning a welcome note is used in our example.

At this point, we have successfully created a service.

Inject and use a service
Think of it like this: if you are building a car, instead of the car having to make its own engine, wheels, and seats, someone (like a supplier) gives those parts to the car so it can assemble them.

Dependency injection (DI) is a way to provide components with access to services and other resources.

In our example, we will inject our ‘MyFirstService’ in the ‘app component’ and use the getGreeting function. This will allow us to reuse the function. Remember that, the same steps apply to any component you would want to inject the service.

Open the component you want to inject the service and pass the service in the constructor.
In our case, we will do it in the app.component.ts

Create a function that will call the required function from the service. You can also call it from the ngOnInit as well. It all depends on your use cases.

Create the html template to get and display the information and trigger the function call.
In our case, we will create in the app.component.html

Note. On line 2, we are using [(ngModel)]. This is called 2-way binding.
When using it, you need to add ‘FormsModule’ under ‘imports’ in the component’s module file; in our case, app.module.ts.

Below is what the end result looks like:

Conclusion
Angular's core ideas of services and dependency injection aid in organizing your application in a way that is modular, testable, and manageable. Dependency injection makes sure that these services are delivered in a flexible and effective way, while services allow you to encapsulate reusable functionality and communicate data across many components. Correct DI setup enables loose connection between services and components, which facilitates code scalability and modification as your application expands. You can write code that follows best practices in Angular development and is cleaner and easier to maintain if you have a firm grasp of services and DI.

In order to guarantee a seamless user experience and facilitate debugging, Angular error management entails recording and controlling errors. Angular comes with a number of built-in tools and methods for methodically managing faults.

1. Managing Errors in HTTP
The HttpClient and the catchError operator from RxJS can be used to manage errors in HTTP requests.

For instance
import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { catchError, throwError } from 'rxjs';

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

  constructor(private http: HttpClient) {}

  getData() {
    return this.http.get(this.apiUrl).pipe(
      catchError(this.handleError)
    );
  }

  private handleError(error: HttpErrorResponse) {
    if (error.error instanceof ErrorEvent) {
      // Client-side error
      console.error('Client-side error:', error.error.message);
    } else {
      // Server-side error
      console.error(`Server-side error: ${error.status} - ${error.message}`);
    }
    return throwError(() => new Error('Something went wrong; please try again later.'));
  }
}

catchError: Intercepts errors and allows custom handling.
throwError: Re-throws the error after handling it for further processing.

2. Global Error Handling
Angular provides a way to handle application-wide errors using the ErrorHandler service.

Custom Global Error Handler.
Create a custom error handler.
import { ErrorHandler, Injectable, NgZone } from '@angular/core';

  @Injectable()
  export class GlobalErrorHandler implements ErrorHandler {
    constructor(private ngZone: NgZone) {}

    handleError(error: any): void {
      // Log the error to the console or a logging service
      console.error('Global Error:', error);

      // Notify the user (e.g., using a toast or modal)
      this.ngZone.run(() => {
        alert('An unexpected error occurred.');
      });
    }
  }
   
Register the error handler in AppModule.
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { GlobalErrorHandler } from './global-error-handler';

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule],
  providers: [{ provide: ErrorHandler, useClass: GlobalErrorHandler }],
  bootstrap: [AppComponent]
})
export class AppModule {}

The service will be used throughout the entire application to catch logs.

3. Error Interceptors
Use an HTTP interceptor to handle errors globally for all HTTP requests.

Example
Create an HTTP interceptor.
  import { Injectable } from '@angular/core';
  import { HttpInterceptor, HttpRequest, HttpHandler, HttpErrorResponse } from '@angular/common/http';
  import { catchError, throwError } from 'rxjs';

  @Injectable()
  export class ErrorInterceptor implements HttpInterceptor {
    intercept(req: HttpRequest<any>, next: HttpHandler) {
      return next.handle(req).pipe(
        catchError((error: HttpErrorResponse) => {
          // Handle different error types
          if (error.status === 404) {
            console.error('Not Found:', error.message);
          } else if (error.status === 500) {
            console.error('Server Error:', error.message);
          }

          // Optionally, rethrow the error
          return throwError(() => new Error('An error occurred. Please try again later.'));
        })
      );
    }
  }   

Register the interceptor in AppModule.
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { AppComponent } from './app.component';
import { ErrorInterceptor } from './error-interceptor';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: ErrorInterceptor,
      multi: true
    }
  ],
  bootstrap: [
    AppComponent
  ]
})
export class AppModule {}

4. Using Angular Guards for Route Error Handling
Angular guards can protect routes and handle access-related errors.
import { Injectable } from '@angular/core';
import { CanActivate, Router } from '@angular/router';

@Injectable({
  providedIn: 'root',
})
export class AuthGuard implements CanActivate {
  constructor(private router: Router) {}

  canActivate(): boolean {
    const isAuthenticated = false; // Replace with actual authentication logic
    if (!isAuthenticated) {
      alert('You are not authorized to access this page.');
      this.router.navigate(['/login']);
      return false;
    }
    return true;
  }
}

5. Error Display in the UI
Display user-friendly error messages in the UI using Angular components.

Example
Create an error message component.
import { Component, Input } from '@angular/core';

@Component({
  selector: 'app-error-message',
  template: `
    <div *ngIf="errorMessage" class="error">
      {{ errorMessage }}
    </div>
  `,
  styles: [
    `
      .error {
        color: red;
      }
    `,
  ],
})
export class ErrorMessageComponent {
  @Input() errorMessage: string | null = null;
}

Use the component.
<app-error-message [errorMessage]="error"></app-error-message>

6. RxJS Error Handling Strategies
    Retry Failed Requests.
    import { retry } from 'rxjs';

    this.http.get(this.apiUrl).pipe(
      retry(3), // Retry up to 3 times
      catchError(this.handleError)
    );

Fallback Data.
this.http.get(this.apiUrl).pipe(
  catchError(() => of([])) // Return fallback data on error
);

7. Logging Errors
Use external services like Sentry, LogRocket, or custom logging services to log errors.

Example
@Injectable({
  providedIn: 'root'
})
export class LoggingService {
  logError(message: string, stack: string) {
    // Send error logs to an external server
    console.log('Logging error:', message);
  }
}

The use of "pipes" is one of Angular's most potent tools for formatting and changing data inside templates. Developers can apply transformations like formatting dates, changing text cases, or even filtering data in an efficient and reusable way by using pipes, which offer a declarative mechanism to handle data before it is shown to the user.

Writing clean, manageable, and modular code for Angular applications requires an understanding of pipes. The main distinctions between pipes and functions will be discussed in this post, along with how to use built-in pipes and make your own custom pipes to increase Angular's functionality. You will have a firm grasp on how to integrate pipes into your Angular projects to improve user experience and expedite data presentation by the end of this tutorial.

What is an Angular Pipe?
In Angular, a pipe is a way to transform data before it is displayed in the user interface. Pipes can be used in templates to modify or format data without having to alter the original data.

Pipes are an Angular concept, not a TypeScript (TS) feature. They are a core part of Angular’s template syntax and are used to transform data in the view (template) layer of Angular applications.

Key Points about Pipes in Angular

• Angular-Specific: Pipes are a built-in feature of the Angular framework designed to be used in Angular templates. They are not a native feature of JavaScript or TypeScript.
• Purpose: Their primary function is to transform data in the template before it is displayed to the user. This transformation can include formatting dates, numbers, currencies, filtering arrays, or performing more complex data transformations.

Declarative Transformation: Pipes enable declarative transformation of data within the template, meaning that the logic for transforming data is cleanly abstracted away from the component’s TypeScript code.

You may be wondering why we should use Pipes when we can use functions.

Types of Pipes
There are two types of Pipes.
Pure Pipe (Default): A pure pipe will only re-run when its input value changes.
    @Pipe({

      name: 'pureExample',

      pure: true // This is the default value, so you can omit this

    })

    export class PureExamplePipe implements PipeTransform {

      transform(value: any): any {

        console.log('Pure pipe executed');

        return value;

      }

    }

Impure Pipe: An impure pipe will re-run whenever Angular detects a change in the component’s state, even if the input value hasn’t changed.
@Pipe({
  name: 'impureExample',
  pure: false // Set to false to make it impure
})
export class ImpureExamplePipe implements PipeTransform {
  transform(value: any): any {
    console.log('Impure pipe executed');
    return value;
  }
}

In Angular, you can use in-built pipes or create your own.

In-built pipes
Angular provides some basic pipes that can be used.
It comes from the '@angular/common' package.

Some popular ones that can be helpful are:
CurrencyPipe, DatePipe, DecimalPipe, LowerCasePipe, UpperCasePipe and TitleCasePipe

How to use an in-built pipe?
In your ts file, define your variable. In our example, we will use the variable title.
title = 'app works!';

In your html, you can use the pipe as follows:
<h1> {{title | uppercase}} </h1>

The result is how the string title is displayed:

Note. The currency ‘USD’ is added in front because of the currency pipe, and only 10 characters are displayed because of the slide pipe.

Custom pipes
Run the command below to create a pipe file:
ng generate pipe <<pipe-name>>.

For example: ng generate pipe my-custom-pipe. Once executed, the two files below will be created

Open the file ‘my-custom-pipe.pipe.ts. You will see the following boilerplate code provided:
import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'myCustomPipe'
})
export class MyCustomPipePipe implements PipeTransform {
  transform(value: any, args?: any): any {
    return null;
  }
}

After the default class, you can create the function for your new pipe. In our case, we will create a pipe that will replace spaces in a hyphen. It is important to add the decorator ‘@Pipe’ before the class so that Angular knows what follows will be a pipe. Also, pass the name of the pipe as a parameter in the ‘@Pipe’ decorator. Also, when creating the class, implement ‘PipeTransform’. The resulting class will be as follows:
@Pipe({name: 'removeWhiteSpace'})
export class RemoveWhiteSpacePipe implements PipeTransform {
  transform(value: string): string {
    return value.replace(/\s+/g, '-');
  }
}

The resulting class will be as follows (the full code):
import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'myCustomPipe'
})
export class MyCustomPipePipe implements PipeTransform {


  transform(value: any, args?: any): any {
    return null;
  }
}

@Pipe({name: 'removeWhiteSpace'})
export class RemoveWhiteSpacePipe implements PipeTransform {
  transform(value: string): string {
    return value.replace(/\s+/g, '-');
  }
}

In the ts file of your component, create the variable that will hold the value that will be transformed
textWithSpaces = 'This is a text with a lot of spaces that will be transformed';

In the html file of your component, do the following:
<p>{{ textWithSpaces | removeWhiteSpace }}</p>

The result is the following:

Conclusion
An effective and potent method for formatting and transforming data in the templates of your application is to use angular pipes. Without having to code repetitious logic in your components, you can quickly manipulate data types like strings, dates, and numbers by utilizing built-in pipes. More freedom is provided by custom pipelines, which let you design modular, reusable, and maintainable transformation logic that is suited to your particular requirements.

Understanding the distinction between pipes and functions is key to leveraging their full potential. While functions provide a direct way to execute code, pipes offer a declarative approach to handle transformations directly within templates, improving readability and performance.

Whether you're working with Angular’s built-in pipes or creating custom ones, the ability to easily manipulate data in the view layer is a significant advantage in building dynamic and user-friendly applications. By mastering Angular pipes, you can keep your code clean, concise, and aligned with best practices, ultimately leading to more maintainable and scalable applications.

With the knowledge of how to use and create pipes, you’re now equipped to enhance your Angular applications with powerful data transformations, making your development experience more efficient and enjoyable.

More than four years ago, on January 15, 2021, Debugger for Chrome wrote the post Debug Angular (1) in VS Code. With 208K readings, that article is really popular. This indicated that while Angular is a very popular tool for web development, it is difficult to persuade many developers to focus on its devugging technology. Although this article is a supplement to the original, I am aware that the Visual Studio Code Debugger for Chrome has been deprecated. We'll check if the original article is still relevant or valid.

Debug Angular in VS Code
Now the current VS Code is with v1.95.3. The VS Code Debugger for Chrome is deprecated:

However, user is introduced to use the JavaScript Debugger extension instead. Click the link, we can see that

this extension is already installed if you use VS Code or Visual Studio:

And furthermore,

Nightly Extension you may want to install our nightly build to get the latest fixes and features. The nightly build runs at 5PM PST on each day that there are changes. You can get Nightly extension from JavaScript Debugger (Nightly) - Visual Studio Marketplace, or search in VS Code extension for
@id:ms-vscode.js-debug-nightly

Debugging in VS Code

Actually, the debugging is the same way as we introduced in article, Debug Angular (1), In VS Code by Debugger for Chrome, we will not repeat the process, but given here the major points:

Configure the launch.json file --- choose the port as your app running

Run the app from the Angular CLI (very important, otherwise, the debugging will not work) by command.
Start to debug.

I'm a slack backend.net developer. I have some knowledge of.net technologies, however I'm not very knowledgeable with Angular, a frontend JavaScript framework. In order to enable external communication between the front-end and RESTful web API services, my manager instructed me to jot down certain typescript codes. You all know what would happen if I told him I didn't know how to do it. Anyhow, let's return to the primary topic. Please be aware that this is only intended for novice users who want to fire once and forget. Please don't hold me responsible. My knowledge of typescripts is rather limited.

Resolution and Schematic Design

• I divided the entire assignment into four sections at first:
• Examining the options in the app.
• Setting up an environment depends on whether it's for production, QA, or development.
• Establishing a connection with external RESTful web API services.
• Requests to the services that include instructions or questions.

Basic knowledge - I guess you know it. So, in short.

• Restful web API: it’s an interface for communication with two or more applications.
• TypeScript: Compared to javaScript, It supports writing code with object-oriented concepts.
• Singleton design pattern: It creates a single shared instance of the object.
• Dependency injection design pattern: It is a style of object configuration in which objects are set by an external entity.

Explanation of each of the steps

• Step 1: Read all the configuration at runtime from the appSettings.json file so that applications can use this data at runtime.
• Step 2: Check the environment. Is it development, QA, or production? Set the environment settings data that you got from step 1.
• Step 3: Create a base class for the service to get the API service, for instance. Design it using the concept of the singleton design pattern. Get the settings data from step 2.
• Step 4: The main service class calls all the get/post/put/patch/delete required requests to the RESTful web API. Add the base class from step 3.
• Step 5: Use the dependency Injection pattern to inject the dependent service. Inject the dependent service class into the component class. Call the required methods of the service from the component class. Use the class from step 4.

Implementation of each of the classes using typeScript in the Angular project

• appsettings-json-reader package: Read all the data from the JSON file.
• npm install appsettings-json-reader

Axios package: Promise-based API method called.
npm install axios --save

I guess you already know how to implement step1 & step2.

Implementing steps 3
Creating the base class using a command.
ng g class BaseApiClientService

import { Injectable } from "@angular/core";
import axios from "axios";
import { AppSettingsConfig } from "../../configuration/app-settings-config";

@Injectable()
export class BaseApiClientService {
  private appSettings!: AppSettingsConfig;
  private helloApiBaseUrl!: string;

  constructor() {
    // Holding configuration-data object.
    this.appSettings = new AppSettingsConfig();

    // Getting base URL of the Hello-API.
    this.helloApiBaseUrl = this.appSettings.apiEndPoint;
  }

  // Main API Instance.
  readonly HelloApiInstance = () => {
    return axios.create({
      baseURL: this.helloApiBaseUrl,
      timeout: 5000,
      headers: {
        Accept: 'application/json',
        cors: true,
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'GET, PUT, POST, DELETE, PATCH, OPTIONS',
      }
    });
  }
}

Implementing steps 4
Creating the service class using a command.
ng g service Hello-Api-Service

import { Injectable } from '@angular/core';
import { AxiosInstance } from 'axios';
import { ConstApiSubPathConfig } from '../../configuration/const-api-sub-path-config';
import { BaseApiClientService } from './base-api-client-service';

@Injectable({
  providedIn: 'root'
})
export class HelloAPIServiceService {
  readonly helloWebApiInstance: AxiosInstance;

  constructor(private baseClient: BaseApiClientService)
  {
    this.helloWebApiInstance = this.baseClient.HelloApiInstance();
  }

  GetHelloDataList(isActive:boolean) {
    //// It will add the pathSufix with the main base URL path.
    let pathSufix = '/' + ConstApiSubPathConfig.HelloApiSubDaListPathSufix;

    //// Get request:Returns the response.
    return this.helloWebApiInstance.get(pathSufix, {
      params: { IsActive: isActive }});
  }

  AddHelloMessage(helloMessageObj: any) {
    let pathSufix = '/' + ConstApiSubPathConfig.HelloApiSubPathSufix;

    //// Post request:Returns the response.
    return this.helloWebApiInstance.post(pathSufix, helloMessageObj);
  }
}

Implementing Steps 5
Creating the component class using a command.
ng g component HelloServiceGrid --module app

import { Component } from '@angular/core';
import { HelloAPIServiceService } from '../../../core/service/axios-service/hello-api-service.service';

@Component({
  selector: 'app-hello-service-grid',
  templateUrl: './hello-service-grid.component.html',
  styleUrls: ['./hello-service-grid.component.css']
})
export class HelloServiceGridComponent {
  constructor( private api: HelloAPIServiceService){  }
  getHelloDataList()
  {
      let isActive:boolean = true;
      this.api.GetHelloDataList(isActive)
      .then(response => {

        //// if status-code is success.
        if (response.status === 200) {
          /// Response Data from API.
          let result = response.data;

          //// Implement your logic with the data below:
        }
      }).catch(error => console.log('Error message =====> Sorry : ' + error.message));
  }
}

Don’t forget to check the App.module.ts file. Your components should be added to the declarations array, and your services should be added to the providers array.

I'll go over how to define environmental configurations and read configurations at runtime in the next section, which covers leveraging Azure DevOps CI/CD pipelines to deploy an Angular app to the Azure environment. Anyhow, I have to leave.

React and Angular are two of the most widely used front-end frameworks for creating contemporary online apps. Both are supported by sizable groups and have distinct advantages, yet they serve varying needs and tastes. We'll go over the main distinctions between Angular and React in this post to assist you in choosing the right framework for your project.

Overview

1. React
   • Developed by: Facebook
   • Initial Release: 2013
   • Type: JavaScript library for building user interfaces, primarily focused on rendering UI components.
   • Learning Curve: Moderate
   • Main Concept: React is centered around components and follows a unidirectional data flow.
2. Angular
   • Developed by: Google
   • Initial Release: 2016 (as Angular 2, the complete rewrite of AngularJS)
   • Type: Full-fledged framework for building web applications.
   • Learning Curve: Steep
   • Main Concept: Angular is an opinionated framework that provides a comprehensive solution for building large-scale applications, including built-in features like routing, state management, and HTTP services.

Architecture

1. React
   • Component-Based: React is all about components. Each piece of UI is a component that can manage its state and be reused throughout the application.
   • Virtual DOM: React uses a virtual DOM to optimize rendering performance. When the state of a component changes, React updates the virtual DOM and then efficiently updates the real DOM.
   • Flexibility: React offers flexibility by allowing developers to choose their own libraries for routing, state management, and other needs. This makes React a "view library" rather than a full-fledged framework.
2. Angular
   • MVC Architecture: Angular follows the Model-View-Controller (MVC) pattern, which helps in separating the concerns of data (Model), UI (View), and logic (Controller).
   • Real DOM: Unlike React, Angular directly interacts with the real DOM, which can impact performance in complex applications. However, Angular mitigates this with its change detection mechanism.
   • Built-In Features: Angular comes with a range of built-in features like form validation, HTTP client, routing, and RxJS for reactive programming. This makes Angular a complete solution for building applications without relying on external libraries.

Performance

1. React
   • Virtual DOM: React’s virtual DOM significantly improves performance by minimizing the number of direct manipulations to the real DOM.
   • Component Reusability: React’s component-based architecture promotes reusability, which can lead to better performance in large applications.
   • Bundle Size: React itself is relatively lightweight, but depending on the additional libraries you use, the bundle size can grow.
2. Angular
   • Change Detection: Angular’s change detection mechanism can sometimes lead to performance bottlenecks in large applications, but it also provides tools like OnPush strategy and NgZone to optimize performance.
   • Ahead-of-Time (AOT) Compilation: Angular’s AOT compilation improves performance by compiling the application during the build process, reducing the load time.
   • Built-In Features: While Angular’s rich feature set can impact performance, the framework’s ability to optimize these features mitigates the impact.

Learning Curve

1. React
   • JSX: React uses JSX, a syntax extension that allows you to write HTML within JavaScript. While some developers find JSX intuitive, others might find it challenging initially.
   • Flexibility: React’s flexibility means you need to learn how to integrate and use various libraries for routing, state management, etc., which can be both an advantage and a challenge.
   • Documentation and Community: React has extensive documentation and a large community, making it easier to find resources, tutorials, and third-party libraries.
2. Angular
   • Steep Learning Curve: Angular has a steeper learning curve due to its complexity and the number of built-in features you need to understand.
   • TypeScript: Angular is built with TypeScript, a statically typed superset of JavaScript. While this adds benefits like better tooling and error checking, it also requires learning TypeScript if you’re not already familiar with it.
   • Comprehensive Framework: Angular’s opinionated nature means that once you learn the Angular way of doing things, you have a powerful set of tools at your disposal.

Ecosystem and Community

1. React
   • Ecosystem: React has a rich ecosystem with numerous libraries for state management (Redux, MobX), routing (React Router), and more. The flexibility to choose different tools gives developers more control over their stack.
   • Community: React has a large and active community, contributing to a vast array of plugins, tools, and resources.
2. Angular
   • Ecosystem: Angular has a more integrated ecosystem. Many features that require third-party libraries in React are built into Angular, such as routing, HTTP services, and form handling.
   • Community: Angular also has a large community, but it is more centralized around the official Angular resources, documentation, and Google-backed initiatives.

Use Case
React

1. When to Use React
   • You need flexibility in choosing libraries and tools.
   • You prefer a simple, component-based architecture.
   • You are building a project where performance and simplicity are key.
2. Popular Use Cases
   • Single-page applications (SPAs)
   • Static sites with dynamic components
   • Dashboards and data visualization tools

Angular

1. When to Use Angular
   • You are building a large-scale, enterprise-level application.
   • You need a framework with a comprehensive set of tools and built-in features.
   • You prefer an opinionated framework that guides architectural decisions.
2. Popular Use Cases
   • Complex, enterprise-level applications
   • Applications requiring robust form handling and validation
   • Real-time applications with complex state management

Conclusion
The skills of your team and the needs of your project will determine which of React and Angular is best. React is an excellent option for projects where you want more control over the architecture because of its simplicity and versatility. In contrast, Angular offers a feature-rich, opinionated framework right out of the box, making it perfect for enterprise-level apps.

Both Angular and React are effective front-end development tools, and knowing the advantages and disadvantages of each will help you choose wisely for your upcoming project.

In Angular, component routing is usually done via the Router service. This allows you to call or go to a component from another component. Here's how you can make this happen. In the Router Module, define routes. The first step is to configure your routes in your AppRoutingModule (or any other defined routing module). Describe the pathways and the matching parts.

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { ComponentA } from './component-a/component-a.component';
import { ComponentB } from './component-b/component-b.component';

const routes: Routes = [
  { path: 'component-a', component: ComponentA },
  { path: 'component-b', component: ComponentB },
  // Add more routes as needed
];

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

Use RouterLink in Templates
You can navigate to another component using the RouterLink directive in your template (HTML) of the first component.
<!-- component-a.component.html -->
<a [routerLink]="['/component-b']">Go to Component B</a>

Navigate Programmatically Using the Router
You can also navigate programmatically using the Angular Router in your component's TypeScript file.
import { Component } from '@angular/core';
import { Router } from '@angular/router';

@Component({
  selector: 'app-component-a',
  templateUrl: './component-a.component.html',
  styleUrls: ['./component-a.component.css']
})
export class ComponentA {

  constructor(private router: Router) { }

  goToComponentB() {
    this.router.navigate(['/component-b']);
  }
}

In HTML template
<!-- component-a.component.html -->
<button (click)="goToComponentB()">Go to Component B</button>

Outlet to Render Routed Components
Ensure you have a <router-outlet></router-outlet> in your main HTML template (e.g., app.component.html) where the routed components will be displayed.
<!-- app.component.html -->
<router-outlet></router-outlet>

Lazy Loading (Optional)
If you want to load a module lazily, define your route like this.
const routes: Routes = [
  {
    path: 'component-b',
    loadChildren: () =>
      import('./component-b/component-b.module')
        .then(m => m.ComponentBModule)
  }
];

Summary

• RouterLink: For navigation within the template.
• Router.navigate: For programmatic navigation within the component's TypeScript file.
• Router Outlet: Acts as a placeholder in the template where routed components are displayed.

This setup allows you to call or navigate between components effectively in Angular.