How to make dynamic assets injectable?

[s-a]

I try to inject code changes via browser-sync proxy, but my solution causes a full page reload :(

bs.watch('c:/inetpub/wwwroot/Kentico9/CMS/customer/**/*.css').on('change', function (fn, a, b) {
    bs.reload('http://localhost:3000/CMSPages/GetResource.ashx')
    bs.notify(`refreshed ${fn}`)
});

Wondering that

bs.watch('c:/inetpub/wwwroot/Kentico9/CMS/customer/**/*.css').on('change', function (fn, a, b) {
    bs.reload('/CMSPages/GetResource.ashx?stylesheetfile=/customer/Stylesheets/TopicWorlds.css')
    bs.notify(`refreshed ${fn}`)
});

does not work... Is it possible to make such resources injectable?