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Revati S Misra

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Aryan Kumar

Aryan Kumar

22-Nov-2023

Handling errors and exceptions effectively is crucial in Angular applications to ensure a smooth user experience and facilitate debugging. Angular provides various mechanisms to handle errors and exceptions. Here are some common approaches:

1. Global Error Handling with ErrorHandler:

Angular provides an ErrorHandler service that you can extend to create a global error handler for your application. By implementing the ErrorHandler interface, you can customize how errors are handled globally.

typescriptCopy code

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

class CustomErrorHandler implements ErrorHandler {
  handleError(error: any): void {
    // Your custom error handling logic goes here
    console.error('Global error handler:', error);
  }
}

// In your AppModule:
providers: [{ provide: ErrorHandler, useClass: CustomErrorHandler }]

2. HTTP Interceptor for HTTP Errors:

You can use Angular's HTTP interceptors to handle HTTP errors globally. Interceptors allow you to intercept HTTP requests and responses. Here's a simplified example:

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

@Injectable()
export class ErrorInterceptor implements HttpInterceptor {
  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(request).pipe(
      catchError((error: HttpErrorResponse) => {
        // Your HTTP error handling logic goes here
        console.error('HTTP error interceptor:', error);
        return throwError(error);
      })
    );
  }
}

// In your AppModule:
providers: [
  { provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true }
]

3. Component-Level Error Handling:

Handle errors at the component level using the try-catch block or the error event in observables:

typescriptCopy code

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

@Component({
  selector: 'app-root',
  template: '<div>{{ data.property }}</div>',
})
export class AppComponent {
  data: any;

  ngOnInit() {
    try {
      // Some code that may throw an error
      this.data = null;
      console.log(this.data.property);  // This will throw an error
    } catch (error) {
      // Handle the error at the component level
      console.error('Component error:', error);
    }
  }
}

4. Logging:

Utilize logging services, such as Angular's built-in console or third-party logging libraries like ngx-logger, to log errors and exceptions. Logging can provide valuable information for debugging in development and monitoring in production.

5. Error Pages:

Create custom error pages or components to display friendly error messages to users. Angular Router can be used to navigate to error pages based on specific error conditions.

// In your AppRoutingModule:
const routes: Routes = [
  // Other routes
  { path: 'error', component: ErrorComponent },
  { path: '**', redirectTo: '/error', pathMatch: 'full' } // Redirect to error page for unknown routes
];

Remember that the approach you choose may depend on the specific requirements and nature of your application. It's often a good practice to combine multiple strategies for comprehensive error handling in Angular applications.

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