usb-hotplug

Cross-platform USB hotplug listener for Node.js. Native Rust core via nusb -- no libusb, no C dependencies, built-in TypeScript types.

Supports macOS, Linux, and Windows.

Features

• Real-time USB connect/disconnect events
• Built-in debouncing -- OS-level re-enumeration noise (e.g. iPhones) is coalesced into a single event
• List all currently connected USB devices
• Zero JS dependencies -- single native binary
• Full TypeScript support out of the box

Install

npm install usb-hotplug

Quick start

import { watchDevices, stopWatching, listDevices } from "usb-hotplug"

// List devices currently connected
const devices = listDevices()
console.log(devices)

// Watch for connect / disconnect
watchDevices((err, event) => {
  if (err) throw err
  console.log(event.eventType, event.serialNumber)
  if (event.device) console.log(event.device)
})

// Stop when done
process.on("SIGINT", () => {
  stopWatching()
  process.exit(0)
})

API

listDevices(): UsbDevice[]

Returns all currently connected USB devices.

watchDevices(callback, debounceMs?): void

Starts listening for USB hotplug events. Only one watcher can be active at a time.

Parameter	Type	Default	Description
callback	(err, event) => void	--	Called for each event
debounceMs	number	500	Debounce window in ms

The debounce window coalesces rapid event bursts caused by OS-level USB re-enumeration (a device appearing to disconnect and reconnect within milliseconds). With the default 500 ms window, you receive exactly one Connected event per physical plug-in.

stopWatching(): void

Stops the active watcher. The background thread exits after the current event or on process exit.

Types

interface UsbEvent {
  eventType: "Connected" | "Disconnected"
  deviceId: string
  serialNumber?: string
  device?: UsbDevice       // present on Connected, absent on Disconnected
}

interface UsbDevice {
  vendorId: number
  productId: number
  manufacturer?: string
  product?: string
  serialNumber?: string
  deviceClass: number
  deviceSubclass: number
  deviceProtocol: number
  busId: string
  deviceAddress: number
}

Platform support

Platform	Architecture	Status
macOS	arm64, x86_64	Supported
Linux	x86_64	Supported
Windows	x86_64	Supported

Building from source

Requires Rust and Node.js >= 16.

npm install
npm run build

License

MIT