Installing an NPM package on Bangle.js 2?

When using the library with a real-world sample of 250 values (not just [1,2,3,4]), I seem to get a timeout problem ("Prompt not detected - upload failed")

Yes, that's just that it's taking a while to execute - and when you upload via the IDE it checks that after the upload completes the device responds within a certain time.

If you can upload the minified file (discrete-wavelets.umd.min.­js) instead, that will run a bit faster... And looking at the code there it's quite simple and there are likely quite a few things you could do to get it running more efficiently (like telling Espruino to keep functions that get called often in RAM, and maybe even asking it to JIT compile some) if you do need the extra speed.