nvm.el 
Manage Node versions within Emacs
Installation
Add nvm to your Cask file:
(depends-on "nvm")DSL
nvm-use (version &optional callback)
Use version. If callback is specified, use version in that
callback and then switch back to the previously used version.
nvm-use-for (&optional path callback)
Read version from .nvmrc in path (or default-directory) and use
that. Second callback argument is same as for nvm-use.
nvm-use-for-buffer ()
Call nvm-use-for on the file visited by the current buffer. Suitable
for use in a mode hook to automatically activate the correct node
version for a file.
Contribution
Contribution is much welcome!
Install cask if you haven't already, then:
$ cd /path/to/nvm.el
$ cask
Run all tests with:
$ make