react-native-midi

React-native module for accessing USB midi controllers (on Android). Plans to include Bluetooth and iOS support eventually.

Getting started

$ npm install react-native-midi --save

Installation

Add USB feature in android/src/main/AndroidManifest:

<manifest>

    <uses-feature android:name="android.hardware.usb.host" /> <!-- HERE!-->
    <uses-feature android:name="android.software.midi" android:required="true"/> <!-- HERE!-->

    <application>
      ...
    </application>
</manifest>

Usage

The library is mostly event driven, with a few helper functions for getting the current state of the midi controllers.

Example

import Midi from 'react-native-midi';

// Register for some common events:
Midi.on(Midi.INPUT_DEVICE_ATTACHED, device => {
  console.log(`Device "${device.id}" connected`);
});

Midi.on(Midi.INPUT_DEVICE_DETACHED, device => {
  console.log(`Device "${device.id}" disconnected`);
});

Midi.on(Midi.NOTE_ON, event => {
  console.log(`Device "${event.device}" started note: ${event.note}`);
});

Midi.on(Midi.NOTE_OFF, event => {
  console.log(`Device "${event.device}" stopped note: ${event.note}`);
});

// Stop listening to note events
Midi.off(Midi.NOTE_ON);
Midi.off(Midi.NOTE_OFF);

// Getters
const devices = await Midi.getDevices(); // Currently attached devices
const deviceCount = await Midi.getDeviceCount(); // Number of devices currently attached
const device = await Midi.getDevice(123); // Get device with id '123'

Functions

Function	Arguments	Returns	Description
on	Event, callback		Registers listener for Event. Invokes callback until unregistered
off	Event		Unregisters listener
getDevices		Promise<Device>	Gets connected devices
getDeviceCount		Promise<Number>	Gets number of connected devices
getDevice	deviceId	Promise<Device>	Gets connected device by id

Events

Device Attach/Detach Events

• DEVICE_ATTACHED
• DEVICE_DETACHED
• INPUT_DEVICE_ATTACHED
• INPUT_DEVICE_DETACHED
• OUTPUT_DEVICE_ATTACHED
• OUTPUT_DEVICE_DETACHED

All of these attach/detach events invoke the callback with the following Device object:

{
  id, // Id matches the 'device' property of midi events
  protocol,
  subclass,
  name,
  productId,
  vendorId,
  interfaces,
  configurations, // >= Android "Lollipop"
  serialNumber, // >= Android "Lollipop"
  version, // >= Android "M"
  deviceAddress, // I/O device only
  manufacturerName, // I/O device only
  productName // I/O device only
}

Example

Midi.on(Midi.INPUT_DEVICE_ATTACHED, device => {
  console.log(`Device "${device.name}" by ${device.vendorId} has attached`);
});

Midi Events

All midi event listeners invoke the callback with an object containing a device (int) and cable (int) property, in addition to those properties listed below:

• MISC_FUNCTION_CODES
  • codes (byte[])
• CABLE_EVENTS
  • events (byte[])
• SYSTEM_COMMON_MESSAGE
  • message (string)
• SYSTEM_EXCLUSIVE
  • message (string)
• NOTE_ON
  • channel (int)
  • note (int)
  • velocity (int)
• NOTE_OFF
  • channel (int)
  • note (int)
  • velocity (int)
• POLYPHONIC_AFTERTOUCH
  • channel (int)
  • note (int)
  • pressure (int)
• CONTROL_CHANGE
  • channel (int)
  • function (int)
  • value (int)
• PROGRAM_CHANGE
  • channel (int)
  • program (int)
• CHANNEL_AFTERTOUCH
  • channel (int)
  • pressure (int)
• PITCH_WHEEL
  • channel (int)
  • amount (int)
• SINGLE_BYTE
  • byte (byte)
• TIME_CODE_QUARTER_FRAME
  • timing (int)
• SONG_SELECT
  • song (int)
• SONG_POSITION_POINTER
  • position (int)
• TUNE_REQUEST
• TIMING_CLOCK
• START
• CONTINUE
• STOP
• ACTIVE_SENSING
• RESET

Example

Midi.on(Midi.NOTE_ON, event => {
  console.log(`Device "${event.device}" started note: ${event.note}`);
});

Contributing

Open to pull requests! I'm looking for someone to take on the iOS support in particular as I'm lacking devices to develop on.

TODO

• iOS support
• Bluetooth support
• Document event bodies