music-key

music-key is a collection of functions to create and manipulate music keys:

var key = require('music-key')
key('###') // => 'A major'
key.signature('A major') // => '###'
key.altNotes('A major') // => ['F#', 'C#']
key.relative('minor', 'A major') // => 'F minor'

This is part of tonal

Installation

Via npm: npm i --save music-key

User guide

Valid keys

A key in music-key is a string with a tonic and (optionally) a mode: 'C', 'C major','C minor','Ab dorian' are valid keys. The valid modes are: major, minor, ionian, dorian, phrygian, lydian, mixolydian, aeolian and locrian (major if not specified).

Create keys

The key function returns a key from a name or from a signature:

key('C major') // => 'C major'
key('C') // => 'C major'
key('#') // => 'G major'
key('bb') // => 'Eb major'

Relative keys

You can get relative keys:

key.relative('minor', 'C major') // => 'A minor'
key.relative('minor', key('#')) // => 'E minor'

This function can be partially applied:

var minor = key.relative('minor')
minor('C major') // => 'A minor'

Get key signature and altered notes

The key signature is a string with the flats or sharps:

key.signature('F major') // => 'b'
key.signature('Eb major') // => 'bbb'
key.signature('A major') // => '###'
key.altNotes('F major') // => ['Bb']
key.altNotes('Eb major') // => ['Bb', 'Eb', 'Ab']
key.altNotes('A major') // => ['F#', 'C#', 'G#']

The altered notes are returned in its proper order:

key.altNotes('F major') // => ['Bb']
key.altNotes('Eb major') // => ['Bb', 'Eb', 'Ab']
key.altNotes('A major') // => ['F#', 'C#', 'G#']

Get key scale

key.scale('C major') // => ['C', 'D', 'E', 'F', 'G', 'A', 'B']

License

MIT License