Javascript (Typescript) library for transposing musical chords within text.
Web app: http://ddycai.github.io/chord-transposer
The source code for the web app demo is on the app
branch: https://github.com/ddycai/chord-transposer/tree/app
Install via npm:
npm install chord-transposer
Import the package using your preferred import syntax:
const Transposer = require('chord-transposer');
import * as Transposer from 'chord-transposer';
import { transpose, Chord, KeySignatures } from 'chord-transposer';
To a certain key signature:
> Transposer.transpose(
"G C Am7 C D7 G\n" +
"Saying I love you is not the words I want to hear from you").toKey('F').toString()
'F Bb Gm7 Bb C7 F\n' +
'Saying I love you is not the words I want to hear from you'
up
or down
any number of semitones:
// Up 7 semitones.
> Transposer.transpose(
"G C Am7 C D7 G\n" +
"Saying I love you is not the words I want to hear from you").up(7).toString()
'D G Em7 G A7 D\n' +
'Saying I love you is not the words I want to hear from you'
// Down 4 semitones.
> Transposer.transpose(
"G C Am7 C D7 G\n" +
"Saying I love you is not the words I want to hear from you").down(4).toString()
'Eb Ab Fm7 Ab Bb7 Eb\n' +
'Saying I love you is not the words I want to hear from you'
If the key signature is not specified, the key will be inferred from the first chord.
> Transposer.transpose('F C7 Bb').toKey('D').toString()
'D A7 G'
> Transposer.transpose('Fm C Ab').toKey('Dm').toString()
'Dm A F'
> Transposer.transpose('A Bmaj CM Dm/F E7/G# Gsus4').toKey('F').toString()
'F Gmaj AbM Bbm/Db C7/E Ebsus4'
> Transposer.transpose('Abm Bbmin C- Ddim Ebaug F+ Gb+5').toKey('Dm').toString()
'Dm Emin Gb- Abdim Aaug Cb+ C+5'
When text is passed into transpose
, it is parsed into Token[][]
where
Token = Chord | string
. You can access these through tokens
to parse
however you like:
> Transposer.transpose('C G Am G7/B C F C F G7\n'+
'O Canada Our home and native land').tokens
[
[
Chord { root: 'C', suffix: '', bass: undefined },
' ',
Chord { root: 'G', suffix: '', bass: undefined },
' ',
Chord { root: 'A', suffix: 'm', bass: undefined },
' ',
Chord { root: 'G', suffix: '7', bass: 'B' },
' ',
Chord { root: 'C', suffix: '', bass: undefined },
' ',
Chord { root: 'F', suffix: '', bass: undefined },
' ',
Chord { root: 'C', suffix: '', bass: undefined },
' ',
Chord { root: 'F', suffix: '', bass: undefined },
' ',
Chord { root: 'G', suffix: '7', bass: undefined }
],
[ 'O Canada Our home and native land' ]
]
You can also parse individual chords:
> const Transposer = require('chord-transposer')
> Transposer.Chord.parse('Cm7/E')
Chord { root: 'C', suffix: 'm7', bass: 'E' }