Shpadoinkle Debug

This package exposes some useful debugging functions for tracing the state of Shpadoinkle applications as they change over time. It exposes 2 type classes currently.

class LogJS (c :: Type -> Constraint) where
  logJS :: c a => a -> JSM ()

class LogJS c => Trapper c where
  trapper :: c a => JSContextRef -> a -> a

These are intended to by used with TypeApplications, so you can choose the means of conversion before passing to console.log. For example:

main :: IO ()
main = runJSorWarp 8080 $ do
  ctx <- askJSM
  simple runParDiff initial (view . trapper @ToJSON ctx) getBody

Will log all state by first encoding to JSON with Aeson, then then logging with JSON.parse so the browser console has the nice native display. If we change it to trapper @Show ctx it will use the Show instance instead.