Yesod cure the "Node.js is cancer"

yesodfib.hs

{-# LANGUAGE TypeFamilies, QuasiQuotes, MultiParamTypeClasses,
             TemplateHaskell, OverloadedStrings #-}
import Yesod

data YesodFib = YesodFib

mkYesod "YesodFib" [parseRoutes|
/ HomeR GET
|]

instance Yesod YesodFib where
    approot _ = ""

fib n | n<2 = 1
      | otherwise = fib (n-2) + fib (n-1)

getHomeR :: Handler RepHtml
getHomeR = defaultLayout [whamlet|Fib 30 = #{show $ fib 30}|]

main :: IO ()
main = warpDebug 3000 YesodFib