midi-player
A MIDI player which sends MIDI messages to connected devices.
This module provides a player which sends MIDI messages to connected devices. It schedules the messages with a look ahead of about 500 milliseconds. It does not directly rely on the Web MIDI API but expects a MIDIOutput to be passed as constructor argument. But theoretically that could be anything which implements the same interface.
Usage
midi-player is published on npm and can be installed as usual.
npm install midi-playerThe only exported function is a factory method to create new player instances.
import { create } from 'midi-player';
// This is a JSON object which represents a MIDI file.
const json = {
division: 480,
format: 1,
tracks: [
{ channel: 0, delta: 0, noteOn: { noteNumber: 36, velocity: 100 } },
{ channel: 0, delta: 240, noteOff: { noteNumber: 36, velocity: 64 } },
{ delta: 0, endOfTrack: true }
]
};
// This is a quick & dirty approach to grab the first known MIDI output.
const midiAccess = await navigator.requestMIDIAccess();
const midiOutput = Array.from(midiAccess.outputs)[0];
const midiPlayer = create({ json, midiOutput });
// All MIDI messages have been sent when the promise returned by play() resolves.
await midiPlayer.play();If you want to play a binary MIDI file you can use the midi-json-parser package to transform it into a compatible JSON representation.