How to replace currentUser?

Question

Node.js

I am writing a site on meteor.js, there is an authorization button on the page, it needs to be hidden when the user is authorized.
I do it like this:

{{#if currentUser}}
тут код кнопки
{{/if}}

But if he is authorized, then the button appears for a moment, and then disappears. I know that this is due to the fact that the meteor does not have time to download user information. What can replace this code?