Trying out bangle.js in the wild

What is the status of Bangle.js and apps displaying a map tile in the background of current track?

If you install the OpenStreetMap app you'll get map tiles in the background. It'll display where you are and will leave a trail - but it doesn't display the currently recorded GPS track on it. There's an issue open for that at https://github.com/espruino/BangleApps/issues/395

What about loading a track file and display in background at the sametime that bangle.js is tracking a new path?

That's not done yet, but would be reasonably easy to add. There is track rendering code in the GPS recorder app.

It'd actually be nice to make the track and map rendering into libraries that can be used by other apps. I think that would open up a lot more possibilities.