JavaScript API function?

I’m interested in using Mautic for a project, but can’t find if a feature is available in the JS API.

I’m very interested in the dynamic content functionality, but am wondering if there is a way to block access to an entire page and show other content if the user doesn’t have a specific tag.

Basically the page would only ask Mautic if the user has a tag and then act appropriately client-side.

I don’t mind if there’s a big piece of JS I’d have to add to the relevant pages or even writing it myself. I’m just wondering if the functions to create such code exist.

Thanks!