You're probably using Espruino 1v87? As I said above, you need one of the latest builds as 1v87 had a bug in promises: http://www.espruino.com/binaries/git/commits/master/
@Gordon started
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.
You're probably using Espruino 1v87? As I said above, you need one of the latest builds as 1v87 had a bug in promises: http://www.espruino.com/binaries/git/commits/master/