Flarum modal : "selector must be either a string or a component."

I have the same issue as the following thread : I want to open the standard LoginModal on click of a button :
https://discuss.flarum.org/d/29965-how-to-use-javascript-to-call-up-the-loginregistration-screen-directly

I have the same code as the best answer and it builds, but the JS console writes the error in the title.

I also tried with the import and new LoginModalor just LoginModal with the same result.

I also notice that :

flarum.core.compat['components/LoginModal']
> undefined