Well, leaving aside the React vs Web Components debate, the only issue is that some folks add technologies like React but forget to remove the old ones as they go. They half-finish the job. Then they do that up to 5 times more...

My advice would be to try to refactor the jQuery app to reduce global state first. For example, use ASTs and other techniques to programmatically determine what global state is used where. Think of it not as “porting” to React, but more as ‘re-writing in React” — the sooner you can finish the rewrite, the better. Take it in smaller, thin, but global (across the whole app) steps, and work to break the app dependencies back down to separate components — this is especially true for CSS, which historically has been global by design for much of its life...

If shipping during a rewrite, make sure you have some very basic tests running. Try to implementation-agnostically look for and click text or otherwise use the web app in your tests, then run the tests before and after making widespread changes... Use screenshots from the tests to quickly visually scan for errors. Pay attention to errors in browser consoles also, if not using TypeScript to its fullest yet.

There's loads written on re-writes.

I may be misreading them, but GP seems to be doing the re-write in the recommended way, small chunks at a time. I think the advice cautioning against wholesale replacement re-writes is sound, but piecemeal transition is much more achievable. I think it took about 5 years to transition Wayfair from asp to PHP one page/system/scheduled task at a time, but the result was a working system at all times that improved with the re-write. Not that I have any love for PHP, but (Classic) asp was even worse. (I can’t speak to asp.net, never used it.)

Asp.net Core is fantastic. ASp.net is ok but not as good.

Asp.net Core is cross platform, has a self hosted https server called Kestrel that is insanely fast, has a really sensible composition of middleware, built in DI, and a strong community. Hangfire is a great job runner, signalr is available with real-time push over web sockets, identity server 4 can handle all your Authn/Authz and Entity Framework Core + Linq is very powerful and a lot faster than the full framework version.

Cool, very good info thank you! I’ve heard great things about .net core but never had the pleasure of using it yet. I would love to play with F#!