How use async service into angular httpClient interceptor

Question

Using Angular 4.3.1 and HttpClient, I need to modify the request and response by async service into the HttpInterceptor of httpClient,

Example for modifying the requ

Answer 1

I am using an async method in my interceptor like this:

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

    public constructor(private userService: UserService) {
    }

    intercept(req: HttpRequest, next: HttpHandler): Observable> {
        return from(this.handleAccess(req, next));
    }

    private async handleAccess(req: HttpRequest, next: HttpHandler):
        Promise> {
        const user: User = await this.userService.getUser();
        const changedReq = req.clone({
            headers: new HttpHeaders({
                'Content-Type': 'application/json',
                'X-API-KEY': user.apiKey,
            })
        });
        return next.handle(changedReq).toPromise();
    }
}