interceptor.ts

import {Injectable} from '@angular/core';
import {HttpEvent, HttpInterceptor, HttpHandler, HttpRequest} from '@angular/common/http';
 
@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  constructor(private auth: AuthService) {}
 
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // Clone the request to add the new header.
    const authReq = req.clone({headers: req.headers.set('Authorization', 'my-token')});
    // Pass on the cloned request instead of the original request.
    return next.handle(authReq);
  }
}