Copy or clone source code into your ixi directory such that it can be found as ixi/Snapchot/{index.js, package.json}.
Your node may be running at this time, and it will hot-load the script.
After you've cloned it, and with a running iri node, run the following command to get the latest snapshot:
curl http://localhost:14265 -X POST -H 'Content-Type: application/json' -d '{"command": "Snapchot.getState"}'