ble-server/ble/index.js

const config = require('../config.json')
const bleno = require('bleno')
const adapterName = 'BLE_Printer'
const serverUUID = config.uuid.main
const localEvent = require('./localEvent') //eslint-disable-line
const MainService = require('./main-service')

bleno.on('stateChange', state => {
  console.log(`bt device state ${state}`)
  if (state === 'poweredOn') {
    bleno.startAdvertising(adapterName, [serverUUID])
  } else {
    bleno.stopAdvertising()
  }
})

bleno.on('advertisingStart', function (error) {
  console.log('on -> advertisingStart: ' + (error ? 'error ' + error : 'success'))

  if (!error) {
    bleno.setServices([new MainService()], error => {
      console.log('set service', error)
    })
  }
})