BangleApps/apps/drained/boot.ts

const { battery: threshold = 5, interval = 10, disableBoot = false }: DrainedSettings
  = require("Storage").readJSON(`drained.setting.json`, true) || {};

drainedInterval = setInterval(() => {
  if(Bangle.isCharging())
    return;
  if(E.getBattery() > threshold)
    return;

  if(disableBoot){
    require("Storage").erase(".boot0");

    Bangle.on("charging", charging => {
      if (charging)
        eval(require('Storage').read('bootupdate.js'));
    });
  }

  load("drained.app.js");
}, interval * 60 * 1000);