GitHub, Ledger Devs Discord, Developer Portal

@ledgerhq/hw-transport-node-hid-singleton

Allows to communicate with Ledger Hardware Wallets.

[Node]/Electron (HID) – uses node-hid and node-usb. Keep transport opened and re-use it as a singleton, one device at a time on a computer but more robust implementation.

Are you adding Ledger support to your software wallet?

You may be using this package to open a USB connection between your desktop application and the device.

For a smooth and quick integration:

• See the developers’ documentation on the Developer Portal and
• Go on Discord to chat with developer support and the developer community.

API

Table of Contents

• TransportNodeHidSingleton
  • Parameters
  • Examples
  • exchange
    • Parameters
  • close
  • isSupported
  • list
  • listen
    • Parameters
  • setDisconnectAfterInactivityTimeout
  • disconnect
  • open
    • Parameters
• onDisconnect

TransportNodeHidSingleton

Extends TransportNodeHidNoEvents

node-hid Transport implementation

Parameters

• device HID.HID

• $1 {context: TraceContext?} (optional, default {})

  • $1.context

Examples

import TransportNodeHid from "@ledgerhq/hw-transport-node-hid-singleton";
...
TransportNodeHid.create().then(transport => ...)

exchange

Exchanges with the device using APDU protocol

Parameters

• apdu Buffer

Returns Promise<Buffer> a promise of apdu response

close

Closes the transport instance by triggering a disconnection after some inactivity (no new open).

Intentionally not disconnecting the device/closing the hid connection directly: The HID connection will only be closed after some inactivity.

Returns Promise<void>

isSupported

list

listen

Parameters

• observer Observer<ListenDescriptorEvent>

Returns Subscription

setDisconnectAfterInactivityTimeout

Disconnects device from singleton instance after some inactivity (no new open).

Currently, there is only one transport instance (for only one device connected via USB).

disconnect

Disconnects from the HID device associated to the transport singleton.

If you want to try to re-use the same transport instance at the next action (when calling open again), you can use the transport instance close method: it will only enable a disconnect after some inactivity.

open

Connects to the first Ledger device connected via USB

Reusing the same TransportNodeHidSingleton instance until a disconnection happens. Pitfall: this implementation only handles 1 device connected via USB

Legacy: _descriptor is needed to follow the Transport definition

Parameters

• _descriptor string
• _timeoutMs number?
• context TraceContext?

Returns Promise<TransportNodeHidSingleton>

onDisconnect

Disconnect event received from the transport instance.

It could be after a disconnection coming from the HID library (e.g. device unplugged) or from the transport instance itself (e.g. close). Clearing the singleton instance. Currently, only 1 device at a time is supported.