react-midi-context

A React component for working with MIDI devices and sending MIDI messages.

Installation

npm install react-midi-context

Usage

Import the MIDIProvider component and wrap it around your app to provide MIDI functionality to your components:

import { MIDIProvider } from 'react-midi-context';

function App() {
  return (
    <MIDIProvider>
      {/* Your app components */}
    </MIDIProvider>
  );
}

MIDIProvider API

The MIDIProvider component provides the following API through the MIDIContext context:

• initializeMIDI: Initializes the MIDI functionality and returns an object with MIDI inputs and outputs.
• openMIDIInput(input, callback): Opens a MIDI input for receiving MIDI messages.
• onMIDIMessage(event): Handles a MIDI input event and returns an object with the MIDI data.
• sendMIDIMessage(props): Sends a MIDI message with the specified properties.
• sendMIDICC(channel, cc, value, device): Sends a MIDI Control Change (CC) message.
• sendMIDINoteOn(channel, pitch, value/velocity, device): Sends a MIDI Note On message.
• sendMIDINoteOff(channel, pitch, value/velocity, device): Sends a MIDI Note Off message.
• getMIDIValue({channel, cc, device}): Retrieves the stored value for a MIDI channel and control change (CC) number.
• midiAccess: The MIDI access object.
• midiInputs: An array of available MIDI inputs.
• midiOutputs: An array of available MIDI outputs.
• connectedMIDIInputs: An array of currently connected MIDI inputs.
• addMIDIInput(input, callback): Adds a MIDI input and opens it for receiving MIDI messages.
• removeMIDIInput(input): Removes a MIDI input and closes it.
• connectedMIDIOutputs: An array of currently connected MIDI outputs.
• addMIDIOutput(output): Adds a MIDI output.
• removeMIDIOutput(output): Removes a MIDI output.
• subscribe(callback): Subscribes to changes in the MIDI context.

Examples

Send a MIDI Control Change (CC) message:

import { useMIDIContext } from 'react-midi-context';

function MyComponent() {
  const { sendMIDICC } = useMIDIContext();

  const handleButtonClick = () => {
    sendMIDICC(1, 64, 127, outputDevice);
  };

  return (
    <button onClick={handleButtonClick}>Send MIDI CC</button>
  );
}

Open a MIDI input and handle incoming MIDI messages:

import { useMIDIContext } from 'react-midi-context';

function MyComponent() {
  const { openMIDIInput, onMIDIMessage } = useMIDIContext();

  useEffect(() => {
    const handleMIDIMessage = (event) => {
      const { data, timeStamp, str } = onMIDIMessage(event);
      // Handle the MIDI message
    };

    const openInput = async () => {
      const input = await openMIDIInput(inputDevice);
      if (input) {
        input.onmidimessage = handleMIDIMessage;
      }
    };

    openInput();

    return () => {
      // Clean up the input
    };
  }, []);

  return (
    // Your component JSX
  );
}

License

This project is licensed under the ISC License.