Just to add that if you're shipping, leaving the tag in the battery would be ideal - you could program the device using Pogo pins from the top, and not even have to remove it from the packaging - which would obviously save you a bunch of time.
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.
Just to add that if you're shipping, leaving the tag in the battery would be ideal - you could program the device using Pogo pins from the top, and not even have to remove it from the packaging - which would obviously save you a bunch of time.