Taking a look at the code, it's a web framework for Haskell with a good amount included like authentication, routing, client-side auto refresh (probably built with web sockets and powered by pglisten), web sockets, a job queue based on postgres.
> The fastest way to build type safe web apps. IHP is a new batteries-included web framework optimized for longterm productivity and programmer happiness
Hence even without that line you could've figured that out with one click. Don't have to spam every release about what the program does, as long as the main repository description (including README.md) does.
Looks really heavy for a Haskell application. You have to install React via NPM as a dependency for IHP to process the JSX, effectively resulting in a framework for Haskell riding a big JS framework.
You can more directly achieve a purely functional approach to DOM interaction without the declarative cleverness of JSX from a tiny understanding of how the DOM works.
There's no react dependency. You can combine it with React if you want to make a hybrid of server-side and SPA, but the standard IHP method is to do just server-side rendering with only a tiny bit of js glue for prefetching and such (IHP has its own HSX syntax that looks a bit like JSX, but is turned into html before being sent to the browser).
I'd not say React is big. Sure it's big in name. But compared code-wise to Angular it's tiny, and just handles the view-side of things.
Besides that I'm not sure what you say is correct. It seems IHP uses HSX, something similar to JSX, but not JSX itself, nor React. The only place I see React mentioned is as a dependency of their "Guide" (some documentation hub their run):
> To access the JavaScript ecosystem we need to add NodeJS to our project.
Both the header and this first sentence imply that this is an optional add-on, not a dependency.
I can also speak from experience and tell you that there is no dependency on react. I've played around with IHP and in its default form the stack resembles Rails: Haskell renders HTML with forms, which submit data to the Haskell server via POST. No JavaScript required at all, much less React.
Very neat project!