You just make an FFI declaration in Haskell: foreign import ccall square :: Int -> Int And use --with-js to link against a JS file: // square.js

You just make an FFI declaration in Haskell: foreign import ccall square :: Int -> Int And use --with-js to link against a JS file: // square.js function square(x) { return x * x; } Using jQuery would be an interesting challenge. I suppose you could just get the jQuery object and go nuts on it unsafely, or write typesafe(ish) wrapper functions to export. The “ccall” convention is also a bit disingenuous. Source: https://github.com/valderman/haste-compiler/blob/master/doc/js-externals.txt https://github.com/valderman/haste-compiler/blob/master/doc/...