how can Angular6 be implemented in conjunction with rxjs when asynchronously requesting background data?
watched the video tutorial of Angular4, which is basically the same, but here (asynchronous request for background data)
is not consistent in usage, resulting in code failure, unable to implement the case in the video, and request guidance

this.http.get(this.url).pipe(map((res:Response)=>res.json()));

the above code failed. If you write it like this, can you provide a code that passed the test? thank you very much