Yes, there are plans to have stack perform the GHCJS setup as well. The main blocker as I understand it is that GHCJS is not on Hackage yet (or following any kind of "formal" release process), but Luite announced at HIW that he intends to upload the first release soon. Aside from that, installing GHCJS is a very different process than installing GHC from a bindist, so it's a matter of putting in the effort to develop and test it.

On Fri, Sep 4, 2015 at 10:41 AM, Michal Antkiewicz <mantkiew@gsd.uwaterloo.ca> wrote:

what a great release! Esp. the reuse of binaries between snapshots!

Support added for compiling with GHCJS
I presume that stack does not assist in installing GHCJS itself as it does for ghc. Are there any plans of improving the ghcjs situation? What are the current blockers?

Thanks,
Michal