fretboard

🎸 Programatically handle the notes of fretted string instruments, like the guitar

Table of Contents

• Install
• Usage
  • Find Notes
  • Change tunings
  • Find notes
• API
  • Fretboard Object
    • Properties
    • Methods
    • Array-like properties & methods
    • Static Methods
  • MusicString Object
    • Properties
    • Methods
    • Array-like properties & methods
  • MusicNote Object
    • Methods
• License

Install

$ npm install --save fretboard

The module has three classes, Fretboard, MusicString, MusicNote, available as follows:

var Fretboard = require('fretboard');
var MusicString = Fretboard.MusicString;
var MusicNote = Fretboard.MusicNote;

A Fretboard is an array-like object of MusicStrings, which are array-like objects of MusicNotes.

Usage

var Fretboard = require('fretboard');
 
var guitar = new Fretboard();
// or, explicitly stating the default tuning and number of frets
var guitar = new Fretboard('EADGBE', 20);
 
// or make your own arrangement of strings and frets
var ukulele = new Fretboard('GCEA', 15);

Compatible with all tunings available in string-tunings. Build yourself a whole string orchestra!

var tunings = require('string-tunings');
var openG = new Fretboard(tunings.guitar.open.G),
     bass = new Fretboard(tunings.bass.standard),
 mandolin = new Fretboard(tunings.mandolin.standard);

Find Notes

A Fretboard is a zero-indexed array-like object of MusicStrings, which are array-like objects of MusicNotes. The 0th element of a string is the open note, and so the 1st element is the 1st fret, etc. Thus, the fretboard acts as a 2D array of note names.

// 1st string, 5th fret should be an A
guitar[0][5]
//=> MusicNote { note: 'A' }
 
ukulele[3][5].note
//=> 'D'

Change tunings

On individual strings:

// tune individual strings to a specific key
guitar[5].tuneTo('D')
guitar[5][0]
//=> MusicNote { note: 'D' }
 
// or a specific number of half steps
guitar[3].tune(-1)
guitar[3].key
//=> 'F#'
 
// Now the tuning is:
guitar.tuning
//=> [ 'E', 'A', 'D', 'F#', 'B', 'D' ]

On the whole fretboard:

// Retune the whole guitar:
guitar.retune('DADGbAD')
guitar.tuning
// flats are converted into sharps.
//=> [ 'D', 'A', 'D', 'F#', 'A', 'D' ]
 
// or tune the whole guitar up or down a number of half steps
guitar.tuneAll(5)
//=> [ 'G', 'D', 'G', 'B', 'D', 'G' ]

Find notes

Retrieve an array of fret numbers corresponding to the note.

On individual strings:

var guitar = new Fretboard('EADGBE', 24);
guitar[0].find('E')
//=> [ 0, 12, 24 ]

On the whole fretboard:

guitar.find('E')
//=> [ [ 0, 12, 24 ],
//     [ 7, 19 ],
//     [ 2, 14 ],
//     [ 9, 21 ],
//     [ 5, 17 ],
//     [ 0, 12, 24 ] ]

API

Fretboard Object

A Fretboard acts as an array of MusicString Objects.

Properties

Property	Type	Description	Default
tuning	Array	the keys of each of the strings	[ 'E', 'A', 'D', 'G' 'B', 'E' ]
numStrings	integer	the number of strings	6
numFrets	integer	the number of frets	20

Methods

fretboard.find( note )

Returns all occurrences of a note across the fretboard in a 2D array of fret numbers. For example, if the first occurrence of an A occurs on the 1st string, 5th fret, fretboard.find('A')[0][0] = 5.

##### fretboard.retune( tuningString )

Re-tunes the fretboard. Must be string of same length as number of strings. Also accepts array of notes.

example:

var bass = new Fretboard('EADG');
 
bass.retune('BEAD')
bass.tuning
//=> [ 'B', 'E', 'A', 'D' ]

fretboard.tuneAll( steps )

Tunes the fretboard up or down a given number of half-steps.

example:

var guitar = new Fretboard();
 
guitar.tuneAll(-2)
guitar.tuning
//=> [ 'D', 'G', 'C', 'F', 'A', 'D' ]
 
guitar.tuneAll(2)
guitar.tuning
//=> [ 'E', 'A', 'D', 'G' 'B', 'E' ]

Array-like properties & methods

These are provided to treat the Fretboard as an array of MusicStrings.

fretboard.length <integer>: equivalent to numStrings

fretboard.forEach( function(element, index, strings) ): an Array.forEach equivalent for the strings

Static Methods

Fretboard.parseTuningString( tuningString )

Parses a string of notes into an array of note names.

example:

Fretboard.parseTuningString('EADGBE')
//=> ['E', 'A', 'D', 'G' 'B', 'E']
 
Fretboard.parseTuningString('GCEA');
//=> ['G', 'C', 'E', 'A']
 
Fretboard.parseTuningString('DADF#AD')
//=> ['D', 'A', 'D', 'F#', 'A', 'D']

---

MusicString Object

A MusicString acts as an array of MusicNote Objects.

Properties

Property	Type	Description	Default
key	String	The note of the open string	Required input
numFrets	integer	The number of frets	20

Methods

musicString.find( note )

Finds all occurrences of a note. Returns an array of the fret numbers.

musicString.tuneTo( note )

Tunes the whole string to a given key.

musicString.tune( steps )

Tune the string up or down a given number of half-steps.

Array-like properties & methods

These are provided to treat the MusicString as an array of MusicNotes.

musicString.length <integer>: equivalent to numFrets

musicString.forEach( function(element, index, strings) ): an Array.forEach equivalent for the notes

---

MusicNote Object

A MusicNote is an object with a note property and the following methods. Sharps (#) are preferred to flats (b), and flats will be translated accordingly.

Methods

None of the methods affect the note value, and all of them have static counterparts.

musicNote.diff( note )

Returns the number of half-steps between the current note and a given one. This is always positive, assuming the current note is lower in pitch.

Static version: MusicNote.diff(note, note)

example:

var note = new MusicNote('A');below
note.diff('G#')
//=> 11
 
note = new MusicNote('G#');
note.diff('A')
//=> 1

musicNote.tuned( steps )

Returns the pitch value of a note that is steps half-steps away.

Static version: MusicNote.tuned(note, steps)

example:

var note = new MusicNote('A');
note.tuned(5)
//=> 'D'
note.tuned(-5)
//=> 'E'

musicNote.up( steps )

Returns the pitch value of a note that is steps half-steps higher.

Static version: MusicNote.up(note, steps)

musicNote.down( steps )

Returns the pitch value of a note that is steps half-steps lower.

Static version: MusicNote.down(note, steps)

musicNote.flat()

Returns the pitch value of the note one half-step lower the note.

Static version: MusicNote.flat(note)

musicNote.sharp()

Returns the pitch value of the note one half-step higher the note.

Static version: MusicNote.sharp(note)

License

MIT © 2016 Robert Pirtle