Request Timeout HTTP Interceptor (Header)

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { RequestTimeoutHttpInterceptor, DEFAULT_TIMEOUT } from './interceptors';
import { AppComponent } from './app.component';

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule,
  ],
  declarations: [
    AppComponent,
  ],
  providers: [
    { provide: HTTP_INTERCEPTORS, useClass: RequestTimeoutHttpInterceptor, multi: true },
    { provide: DEFAULT_TIMEOUT, useValue: 5000 },
  ],
  bootstrap: [AppComponent]
})
export class AppModule { }

timeout.interceptor.ts

import { Injectable, InjectionToken, Inject } from '@angular/core';
import { HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';
import { empty, TimeoutError } from 'rxjs';
import { timeout, catchError } from 'rxjs/operators';

export const DEFAULT_TIMEOUT = new InjectionToken<number>('defaultTimeout');

@Injectable({
  providedIn: 'root'
})
export class RequestTimeoutHttpInterceptor implements HttpInterceptor {

  constructor(
    @Inject(DEFAULT_TIMEOUT) protected defaultTimeout: number,
  ) { }

  intercept(req: HttpRequest<any>, next: HttpHandler) {
    const modified = req.clone({
      setHeaders: { 'X-Request-Timeout': `${this.defaultTimeout}` }
    });

    return next.handle(modified).pipe(
      timeout(this.defaultTimeout),
      catchError(err => {
        if (err instanceof TimeoutError)
          console.error('Timeout has occurred', req.url);
        return empty();
      })
    );
  }

}