[aaron-lebo]

This is very cool. The example apps are relatively slow to load compared to the equivalent in some other frameworks (my favorite is Mithril for an idea of how small/fast these can get).

Was wondering whether it might be a slow server, but the app.js for the TodoMVC appears to be over a megabyte (1.21 MB, have a 4000 line Mithril app which is 500k uncompressed). What's up with that?

[StreamBright]

Can you give exact numbers and a testing method of how you tested and determined it is slow?

[aaron-lebo]

The router example on Github loads ~1.5 MB of JS files. Mithril's entire framework is 8kb gzipped (including a router).

[mbrock]

ghcjs is a pretty heavyweight environment. It's actually translating the compiled core IR from GHC into JavaScript, and including a port of GHC's runtime system.

It can run basically any Haskell library. That includes the ability to run multithreaded Haskell code -- the JS RTS includes a scheduler. You also get Software Transactional Memory. Lazy evaluation works just as usual -- and so on.

The tradeoffs become worth it when you have a sufficiently valuable base of Haskell code that you want to run in the browser, and when your users aren't very constrained by page load time. Say, if you have some complicated tricky logic that you don't want to rewrite in another language, but you want to use it in your web app.