[danneu]

Years ago, I played with the idea: https://github.com/danneu/klobb

I went on to implement it in Swift (https://github.com/danneu/hansel) and then seriously improved on it in Kotlin (https://github.com/danneu/kog).

It was fun but hard to really make a convincing upgrade to Koa once you consider the rest of the ecosystem. For example, since Koa exposes Node's req/res, then you can still use existing Node/Express middleware.

[tlrobinson]

I think it should be possible to write an adapter to use existing Express middleware. I haven't tried, but it's on my TODO list.