In the two REST client (simple & json) provided in the module, on the CREATE operation we have this :
case CREATE:
return { data: { ...params.data, id: json.id } };
params is the data sended by the client to the server, json is the data that the server returned.
Why is better to return client data than server response ?
In the two REST clients, we assume that we can't prejudge what the server will return to us, but the new element's id.
And we're assuming that the data provided for creation will allow the correct display of the list.
But of course, if this is not your case (i.e. you know exactly what the server will return, including some information not requested at creation), you can decorate an existing client or create your own.