I think that running this script on the downloaded Espruino source files might come up with a file for you, but it hasn't been changed in a while so I wonder if it still works:
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
The definitions come from http://www.espruino.com/json/espruino.json, which is in format that works with Tern.
I think that running this script on the downloaded Espruino source files might come up with a file for you, but it hasn't been changed in a while so I wonder if it still works:
https://github.com/espruino/Espruino/blob/master/scripts/build_jsstub.py