Blazor is too closed/hard to customize? My experience trying to make a custom Hash Router

[datvm]

After see #6175, I want to implement my own solution. However, what I thought would be a fun side project turned into frustration. My plan was to simply transform the URL path into hash at the browser end so we can reuse everything else of the current routing system.

• First, I tried extending Router. Nope most of the things are internal or private and there is not even a way to wrap it due to all the injection. Wrapping: not possible, copying the whole code: not possible due to multiple internal classes as well.
• Then I tried a "nuclear" option by replacing Javascript globalThis.location (href) and globalThis.history (for pushState and replaceState). I failed because location cannot be modified in any way: Proxy, defineProperty or even straight up replacing the window object (strangely enough it wasn't a problem with history). Then I go to a milder option of replacing Blazor._internal.navigationManager but still wasn't successful because beside the obvious functions (that barely even called), a few of them can't be modified at all.

So, IMO, for something as important as Routing, it's so hard to intercept and customize. I had a similar frustration before when trying to modify the IJSRuntime object (though in the end I barely made it through by modifying the whole DI thing and wrap it). I wish they either open up more point of customization or stop hiding so many important classes.

What do you think? Do you have any suggestion where I may be able to continue with this? Thanks.