electron/docs/fiddles/features/web-bluetooth/renderer.js

async function testIt () {
  const device = await navigator.bluetooth.requestDevice({
    acceptAllDevices: true
  })
  document.getElementById('device-name').innerHTML = device.name || `ID: ${device.id}`
}

document.getElementById('clickme').addEventListener('click', testIt)

function cancelRequest () {
  window.electronAPI.cancelBluetoothRequest()
}

document.getElementById('cancel').addEventListener('click', cancelRequest)

window.electronAPI.bluetoothPairingRequest((event, details) => {
  const response = {}

  switch (details.pairingKind) {
    case 'confirm': {
      response.confirmed = window.confirm(`Do you want to connect to device ${details.deviceId}?`)
      break
    }
    case 'confirmPin': {
      response.confirmed = window.confirm(`Does the pin ${details.pin} match the pin displayed on device ${details.deviceId}?`)
      break
    }
    case 'providePin': {
      const pin = window.prompt(`Please provide a pin for ${details.deviceId}.`)
      if (pin) {
        response.pin = pin
        response.confirmed = true
      } else {
        response.confirmed = false
      }
    }
  }

  window.electronAPI.bluetoothPairingResponse(response)
})