I say this as a frontend dev--if your goal was to convince backend folks that adopting jsx/tsx is not that complicated, my guess is that your comment won't do that. The setup you described might sound simple to you, but it's not for someone who isn't already familiar with the FE ecosystem. The OP wanted a templating library that is simple to setup and use and would score well with lighthouse, but all of a sudden we're talking about lib.dom.ts files and copy pasting from @types/react.
There was a mention of some familiarity with Typescript and that's all I assumed in my comment. I also said most of the work is optional, especially the type definition work.
lib.dom.ts is one of the many lib files shipped with Typescript itself. I mention @types/react mostly as an example of probably what not to do, but it is a simple Node package maintained by DefinitelyTyped and easy to lookup if you did want to do things the brute force way (as many have, because it is easy to do). I also linked to two different examples of the type definition work, they are small files that are maybe not easy to follow in the way they used advanced concepts of Typescript's type system, but show that you can do a lot without copy and pasting thousands of lines from @types/react. You can replace most of the complex types in either file with `any` and get a quick and dirty minimalist type definition file. (If you go far enough back in the commit history of either the files I posted you can find examples of that, too.)
For what it is worth, I test Butterfloat with JSDOM entirely in Node (after Typescript building) and SSR/SSG/progressive enhancement and other backend support has always been on its roadmap, parts of it exist today and other parts were architected with it in mind, but it just hasn't yet been prioritized (because so far it is admittedly a solo project). I also wanted something that was simple to setup and use, backend or frontend, and would score well on lighthouse but also might score well in Web Components and also make sense replacing old Knockout.JS code from a decade or two ago.
Also, for some of us, no client side rendering is a feature not a deficiency.
I fully understand how to do everything the parent poster said, I just don’t want to do it and don’t think it’s the best dev experience in my use cases.
You can support TSX and not support client side rendering. I never said anything about client-side rendering. There's no client-side dependencies to TSX at all. Even optionally depending on `lib.dom.d.ts` for a nice Types experience from a .d.ts file doesn't really mean a client-side dependency as a types-only dependency.
The functions in Boxwood are so close already to the necessary shape for a JSX function (it's just `jsx(tagNameOrComponentFunction, properties, children)`) there's not a lot you actually need to do to get nearly "free" JSX support even if you didn't want to put the work into a .d.ts file to get nice Types back out and just did `export type JSX.InternalElements = any`.
That said, the point about `lib.dom.d.ts` is that building the types can be a lot easier than it seems and need only a couple dozen lines to support a lot of rich typechecking including MDN documentation links in hover tooltips.
From personal experience, with multiple libraries, it is a really nice developer experience to have good TSX type checking and type documentation. Auto-complete along speeds up template development and the number of times I've used the MDN link in a property (attribute) hover to check support statistics or edge case notes in the documentation is surprisingly high.
