wai-shake provides a command-line tool serve-ghcjs that starts a http server that compiles Haskell files to javascript on the fly using ghcjs. This is meant to enable a workflow -- known from interpreted languages -- that consists roughly of:

• Modifying a source file,
• saving the file,
• reloading the page in the browser.

serve-ghcjs will

• serve the web app (index.html and corresponding javascript files) created by ghcjs,
• recompile the Haskell source files when they changed on disk,
• in case of compilation errors, show the error messages both in the html page and on the javascript console.

Example usage:

serve-ghcjs --port 8080 --main-is src/Main.hs -isrc

Then point your browser to http://localhost:8080.

This is an experimental project and has lots of room for improvement.

• Recompilation could be triggered through inotify to speed things up.
• wai-shake already contains a library which should be used to integrate ghcjs compiled javascript in bigger wai applications. I haven't used it like this though.
• wai-shake should allow to use custom shake rulesets (e.g. for purescript, typescript, minifying, etc.)
• wai-shake could have a production mode, where it performs the build steps at application startup once.
• travis could execute the test-suite. (Currently the test-suite depends on ghcjs in the $PATH, but that takes very long to install. Don't have a good idea how to deal with this.)