How can I use Angular's HttpClient for advanced scenarios?

How can I use Angular's HttpClient for advanced scenarios?

You can use Angular's HttpClient for advanced scenarios by leveraging features like interceptors, observables, and error handling.

What are interceptors and how do they work?

Interceptors are a powerful feature that allows you to modify requests and responses globally. You can use them to add headers, log requests, or handle errors.

Can you show me an example of an interceptor?

Sure! Here's a simple example of an interceptor that adds an authorization token to every request:

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

@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const clonedRequest = request.clone({
      setHeaders: { Authorization: `Bearer YOUR_TOKEN` }
    });
    return next.handle(clonedRequest);
  }
}

How do I handle errors in HttpClient?

You can handle errors by using the catchError operator from RxJS. This allows you to catch errors and return a user-friendly message or a fallback value.