CODE EXAMPLE FOR JAVASCRIPT

middleware for angular for passing token in header

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

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    const token = 'token...'; // your auth token
    if (authorized) { // your authorized  logic
      request = request.clone({
        setHeaders: {
          Authorization: `${token}`
        }
      });
    }

    return next.handle(request);
  }
}