If you've been following Uno Platform, you'll know that the open-source Windows Calculator has already been ported to iOS, Android, and macOS. As an additional proof of multi-platform reach, they've now made it available to Web/WebAssembly.
Try it Live
In this case, Uno Platform utilizes WASM to run XAML and C# in the browser. In addition to helping with UI aspects of the conversion, Uno Platform can help Web app performance by providing a choice of Interpreted Mode, Ahead-of-Time (AoT) or Profile-Guided AoT compilation.
If you're interested you can Read More about the porting process and the different challenges faced.