Unable to override default parameters

[Tombarr]

I'm testing out @minimal-analytics/ga4 on KaiOS apps but I'm running into an issue with because package apps are served with an origin like app://myapp.com/. The document location includes the app: protocol, and Google Analytics appears to discard the page path (but not page title) as a result. In Universal Analytics, I replaced the app: protocol with https: and it worked well.

Looking at getQueryParams, the event parameters are concatenated with the default parameters. If I pass { dl: 'https://myapp.com/index.html' }, it sends two dl parameters because of the behavior of URLSearchParams.

Would you consider changing the behavior to allow overriding default parameter values? This should be a non-breaking change, since anyone attempting to override default parameters now would have a bad request anyway.