npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

midi-writer-js

v3.1.1

Published

A library providing an API for generating MIDI files.

Downloads

993

Readme

♬ MidiWriterJS

npm version Tests Lint Try midi-writer-js on RunKit

MidiWriterJS is a JavaScript library providing an API for generating expressive multi-track MIDI files.

Note that the master branch is in active development so if you're looking for a tried and true stable version please use the latest release.

Source Documentation

Install

npm install midi-writer-js

Getting Started

import MidiWriter from 'midi-writer-js';

// Start with a new track
const track = new MidiWriter.Track();

// Define an instrument (optional):
track.addEvent(new MidiWriter.ProgramChangeEvent({instrument: 1}));

// Add some notes:
const note = new MidiWriter.NoteEvent({pitch: ['C4', 'D4', 'E4'], duration: '4'});
track.addEvent(note);

// Generate a data URI
const write = new MidiWriter.Writer(track);
console.log(write.dataUri());

Documentation

MidiWriter.Track()

  • addEvent({event}, mapFunction)
  • setTempo(tempo)
  • addText(text)
  • addCopyright(text)
  • addTrackName(text)
  • addInstrumentName(text)
  • addMarker(text)
  • addCuePoint(text)
  • addLyric(text)
  • setTimeSignature(numerator, denominator)

MidiWriter.NoteEvent({options})

The MIDI spec defines that each note must have a NoteOnEvent and NoteOffEvent (or NoteOnEvent with zero velocity) event, marking the beginning and end of the sounding note. While it's possible to manually add these events to a track with Track.addEvent(), the NoteEvent provides a more intuitive interface for doing this with a single, "pseudo" event. Under the hood, the NoteEvent event generates the relevant NoteOnEvent and NoteOffEvent events.

Each MIDI event has a delta property, which is used to define the number of ticks to wait after the previous event. This can be challenging to calculate if you're not necessarily adding events in a serial fashion. Because of this, you can alternatively use the tick property to define the exact tick where the event should fall.

The NoteEvent supports these options:

MidiWriter.Writer(tracks)

The Writer class provides a few ways to output the file:

  • buildFile() Uint8Array
  • base64() string
  • dataUri() string
  • stdout() file stream (cli)

Hot Cross Buns

Here's an example of how everyone's favorite song "Hot Cross Buns" could be written. Note use of the mapping function passed as the second argument of addEvent(). This can be used to apply specific properties to all events. With some street smarts you could also use it for programmatic crescendos and other property 'animation'.

import MidiWriter from 'midi-writer-js';

const track = new MidiWriter.Track();

track.addEvent([
		new MidiWriter.NoteEvent({pitch: ['E4','D4'], duration: '4'}),
		new MidiWriter.NoteEvent({pitch: ['C4'], duration: '2'}),
		new MidiWriter.NoteEvent({pitch: ['E4','D4'], duration: '4'}),
		new MidiWriter.NoteEvent({pitch: ['C4'], duration: '2'}),
		new MidiWriter.NoteEvent({pitch: ['C4', 'C4', 'C4', 'C4', 'D4', 'D4', 'D4', 'D4'], duration: '8'}),
		new MidiWriter.NoteEvent({pitch: ['E4','D4'], duration: '4'}),
		new MidiWriter.NoteEvent({pitch: ['C4'], duration: '2'})
	], function(event, index) {
    return {sequential: true};
  }
);

const write = new MidiWriter.Writer(track);
console.log(write.dataUri());

VexFlow Integration

MidiWriterJS can export MIDI from VexFlow voices, though this feature is still experimental. Current usage is to use MidiWriter.VexFlow.trackFromVoice(voice) to create a MidiWriterJS Track object:


// ...VexFlow code defining notes
const voice = create_4_4_voice().addTickables(notes);

const vexWriter = new MidiWriter.VexFlow();
const track = vexWriter.trackFromVoice(voice);
const writer = new MidiWriter.Writer([track]);
console.log(writer.dataUri());

Demos