Help for writing an app (running zones using Karvonnen method)

I checked the swipe and I don't get how the swipe would take me from the running run.js to karvonnen.js (or if I have to merge it in one app).

With regards to separate files vs. merging in your code in run.app.js both approaches are doable. EDIT: But after considering your specification in the OP I think you should try to merge into one file.

I think it may be easiest to define a function handling swipe events in the run app, I usually call them swipeHandler, where you call load('karvonnen.js'). Then doing Bangle.on('swipe', swipeHandler) to make the Bangle listen for swipes and execute the function.

Check out the Espruino Hardware Reference for load(), event swipe, and maybe Bangle.setUI().

If you want to swipe between the regular run app and korvonnen frequently it's maybe better to implement it as one (or several) functions to call inside run.app.js. If you want the run app to work simultaneously as well this will probably be the way to go. EDIT: I believe this is what you want.