@dawcore/midi

Framework-agnostic MIDI file loading and parsing for the dawcore family. No React, no DOM, no Lit — pure functions built on @tonejs/midi.

Used by @dawcore/components (the Lit web component layer, via editor.loadMidi()) and @waveform-playlist/midi (the React useMidiTracks hook).

Installation

npm install @dawcore/midi

No peer dependencies. @dawcore/components declares this package as an optional peer dependency — add it to your own dependencies to enable editor.loadMidi() (it's dynamic-imported on first call, so non-MIDI users ship zero parser bytes).

Quick Start

import { parseMidiUrl, parseMidiFile } from '@dawcore/midi';

// Fetch and parse a .mid URL (optional AbortSignal for cancellation)
const midi = await parseMidiUrl('/media/song.mid');
// midi: { tracks, duration, name, bpm, timeSignature }

for (const track of midi.tracks) {
  // track: { name, notes, duration, channel, instrument, programNumber }
  console.log(track.name, track.notes.length + ' notes');
}

// Or parse an ArrayBuffer you already have (e.g. from a File input)
const buffer = await file.arrayBuffer();
const parsed = parseMidiFile(buffer, { flatten: true }); // merge all tracks into one

Note timings are in seconds, already tempo-adjusted by @tonejs/midi. Tracks without notes are filtered out.

API

• parseMidiFile(data: ArrayBuffer, options?) — parse MIDI data into ParsedMidi
• parseMidiUrl(url: string, options?, signal?) — fetch and parse a .mid URL
• Options: { flatten?: boolean } — merge all MIDI tracks into a single track
• Types: ParsedMidi, ParsedMidiTrack, ParseMidiOptions, MidiLoadOptions, MidiLoadResult

Examples & Documentation

• examples/dawcore-tone/midi-load.html — loading a .mid file (URL or file input) into <daw-editor> via editor.loadMidi(), with cancellation (pnpm example:dawcore-tone)
• MIDI guide — covers both the React (@waveform-playlist/midi) and Web Components (@dawcore/components) paths, which share this package's parser underneath

License

MIT