Pebble has done something quite impressive – they’ve implemented a framework which allows you to write Pebble apps and watchfaces in pure Javascript. They’ve done this by embedding the light-weight JerryScript engine into Pebble OS, which means you can now write apps with absolutely no C code, just pure Javascript.
You can also create these Javascript Pebble apps directly from the CloudPebble IDE:
This is quite impressive, since the Pebble isn’t a very high powered device, with very little RAM and available storage. I’m quite a fan of Javascript, so this news has impressed me quite a bit. Right now it’s still in beta though and has issues such as limited API access on the watch, but I’m sure that Pebble will continue to develop this feature, and one day maybe all Pebble apps will be written in Javascript :).
Pebble has a good guide on how to create JS apps here.