You could use JS classes I believe but that doesn't help you - private fields are still only a JS proposal and not part of standard JS or implemented in Espruino: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields
i could of course just make the functions into public methods, but they aren't that useful outside of the module itself
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
You could use JS classes I believe but that doesn't help you - private fields are still only a JS proposal and not part of standard JS or implemented in Espruino: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields