Any way to save information without writing it to flash? (Must survive app close, doesn't need to survive power off)

Gadgetbridge weather and health information do survive loading another application, but do not >survive power off.

They probably won't survive a reboot though. For example steps are stored in the Bangle and if you reboot (long press reboot) the watch you will lose a days step count as it gets reset to 0. I suspect an app switch does not cause these value to be reset in the ram used by the core Espruino operating system. But a reboot will.

What I suspect is needed long term is a way to request that a variable is made non volatile and stored in the Espruino Ram - that way it will survive an app switch BUT will get reset and cleared if the watch is rebooted. Something like Bangle.writeMemory(INT, 'freds_int', 57); and Bangle.readMemory('freds_int'); might do it. Of course such a scheme would be open to abuse by app writers who could just hog all the ram at the point of boot. So it might not find favour with Gordon.

There are apps that write state to flash using the onKill() event hook. I dont think a few writes a day to flash is going to massively reduce the life of the watch.