yes I think you could still do that if you make your function asynchronious. For example
import {currentMember} from 'wix-members';
$w.onReady(async function () {
let member = await currentMember.getMember()
if(member){some code etc.}
if(!member){some other code}
})
if you want it to be more similar to the wixusers you could make it more compact
if(await currentMember.getMember()){some code etc.}
else{some other code}