Chorus.js: Music Composition in JavaScript

Features

• Compose music with code via multi-track MIDI
  • output real-time MIDI to control synthesizers, samplers, and other MIDI instruments
  • output MIDI files to save your musical ideas with perfect timing
• Explore harmony using scales and chord progressions
• Explore microtonal tunings

Requirements

• Node.js v6+ (browser support is planned)
• Optional: compilation tools for native dependencies
  • If you want real-time MIDI output, follow node-gyp's installation instructions to setup compilation tools
  • Otherwise, ignore non-fatal errors during install. You can still use MIDI file output

Quick Start Guide

1. Install

    npm install chorus

2. Create the file quick-start.js

// quick-start.js 
const { Song, Output } = require('chorus');
require('chorus/names').into(global);

const song = new Song({
  sections: [{
    parts: [{
      pitches: [C4, D4, E4, F4, G4, F4, E4, D4, C4],
    }]
  }]
});

Output.select().then(output => output.play(song));

3. Output a MIDI file

• Run:

    node quick-start.js -f quick-start.mid
          

• Open quick-start.mid in any app that supports MIDI files

4. Output real-time MIDI (requires native dependencies)

• On macOS

  • Download SimpleSynth and launch it

  • Select MIDI Source: SimpleSynth virtual input in SimpleSynth

  • Run:

      node quick-start.js -p simplesynth

• On Windows

  Use the built-in wavetable synth:

   node quick-start.js -p wavetable  

Tutorials

Work in progress!

1. Intro / Setup - The basics of chorus.js and how to setup with a DAW
2. Pitch - how to organize pitch
3. Rhythm - how to organize time
4. Pitch & Harmony - chords
5. Song Structure - how to organize song structure
6. Advanced Features - how to avoid repetition and create variety
7. Microtonality - how to use more than 12 pitches per octave

Project Info

• Full documentation
• Github page