node-ble/example.js

Bluetooth Low Energy (BLE) library written with pure Node.js (no bindings) - baked by Bluez via DBus

require('dotenv').config()

const { createBluetooth } = require('.')
const { TEST_DEVICE, TEST_SERVICE, TEST_CHARACTERISTIC, TEST_NOTIFY_SERVICE, TEST_NOTIFY_CHARACTERISTIC } = process.env

async function main () {
  const { bluetooth, destroy } = createBluetooth()

  // get bluetooth adapter
  const adapter = await bluetooth.defaultAdapter()
  await adapter.startDiscovery()
  console.log('discovering')

  // get device and connect
  const device = await adapter.waitDevice(TEST_DEVICE)
  console.log('got device', await device.getAddress(), await device.getName())
  await device.connect()
  console.log('connected')

  const gattServer = await device.gatt()

  // read write characteristic
  const service1 = await gattServer.getPrimaryService(TEST_SERVICE)
  const characteristic1 = await service1.getCharacteristic(TEST_CHARACTERISTIC)
  await characteristic1.writeValue(Buffer.from('Hello world'))
  const buffer = await characteristic1.readValue()
  console.log('read', buffer, buffer.toString())

  // subscribe characteristic
  const service2 = await gattServer.getPrimaryService(TEST_NOTIFY_SERVICE)
  const characteristic2 = await service2.getCharacteristic(TEST_NOTIFY_CHARACTERISTIC)
  await characteristic2.startNotifications()
  await new Promise(done => {
    characteristic2.once('valuechanged', buffer => {
      console.log('subscription', buffer)
      done()
    })
  })

  await characteristic2.stopNotifications()
  destroy()
}

main()
  .then(console.log)
  .catch(console.error)