tonal-key

key

tonal-key is a collection of functions to query about tonal keys.

This is part of tonal music theory library.

Example

const key = require('tonal-key')
key.scale('E mixolydian') // => [ 'E', 'F#', 'G#', 'A', 'B', 'C#', 'D' ]
key.relative('minor', 'C major') // => 'A minor'

• key
  • .modeNames(alias) ⇒ Array
  • .fromAlter(alt) ⇒ Key
  • .props(name) ⇒ Object
  • .scale(key) ⇒ Array
  • .alteration(key) ⇒ Integer
  • .accidentals(key) ⇒ String
  • .alteredNotes(key) ⇒ Array
  • .chords(name) ⇒ Array
  • .secDomChords(name) ⇒ Array
  • .relative(mode, key)
  • .tokenize(name) ⇒ Array

key.modeNames(alias) ⇒ Array

Get a list of valid mode names. The list of modes will be always in increasing order (ionian to locrian)

Kind: static method of key
Returns: Array - an array of strings

Param	Type	Description
alias	Boolean	true to get aliases names

Example

key.modes() // => [ 'ionian', 'dorian', 'phrygian', 'lydian',
// 'mixolydian', 'aeolian', 'locrian' ]
key.modes(true) // => [ 'ionian', 'dorian', 'phrygian', 'lydian',
// 'mixolydian', 'aeolian', 'locrian', 'major', 'minor' ]

key.fromAlter(alt) ⇒ Key

Create a major key from alterations

Kind: static method of key
Returns: Key - the key object

Param	Type	Description
alt	Integer	the alteration number (positive sharps, negative flats)

Example

var key = require('tonal-key')
key.fromAlter(2) // => 'D major'

key.props(name) ⇒ Object

Return the a key properties object with the following information:

• name: name
• tonic: key tonic
• mode: key mode
• modenum: mode number (0 major, 1 dorian, ...)
• intervals: the scale intervals
• scale: the scale notes
• alteration: alteration number
• accidentals: accidentals

Kind: static method of key
Returns: Object - the key properties object or null if not a valid key

Param	Type	Description
name	String	the key name

Example

var key = require('tonal-key')
key.props('C3 dorian') // => { tonic: 'C', mode: 'dorian', ... }

key.scale(key) ⇒ Array

Get scale of a key

Kind: static method of key
Returns: Array - the key scale

Param	Type
key	String | Object

Example

key.scale('A major') // => [ 'A', 'B', 'C#', 'D', 'E', 'F#', 'G#' ]
key.scale('Bb minor') // => [ 'Bb', 'C', 'Db', 'Eb', 'F', 'Gb', 'Ab' ]
key.scale('C dorian') // => [ 'C', 'D', 'Eb', 'F', 'G', 'A', 'Bb' ]
key.scale('E mixolydian') // => [ 'E', 'F#', 'G#', 'A', 'B', 'C#', 'D' ]

key.alteration(key) ⇒ Integer

Get key alteration. The alteration is a number indicating the number of sharpen notes (positive) or flaten notes (negative)

Kind: static method of key

Param	Type
key	String | Integer

Example

var key = require('tonal-keys')
key.alteration('A major') // => 3

key.accidentals(key) ⇒ String

Get key accidentals: a string with sharps or flats

Kind: static method of key

Param	Type
key	String

Example

import * as key from 'tonal-keys'
key.accidentals('A major') // => "###"

key.alteredNotes(key) ⇒ Array

Get a list of the altered notes of a given key. The notes will be in the same order than in the key signature.

Kind: static method of key

Param	Type	Description
key	String	the key name

Example

var key = require('tonal-keys')
key.alteredNotes('Eb major') // => [ 'Bb', 'Eb', 'Ab' ]

key.chords(name) ⇒ Array

Get key chords

Kind: static method of key

Param	Type	Description
name	String	the key name

Example

key.chords("A major") // => ["AMaj7", "Bm7", "C#m7", "DMaj7", ..,]

key.secDomChords(name) ⇒ Array

Get secondary dominant key chords

Kind: static method of key

Param	Type	Description
name	String	the key name

Example

key.secDomChords("A major") // => ["E7", "F#7", ...]

key.relative(mode, key)

Get relative of a key. Two keys are relative when the have the same key signature (for example C major and A minor)

It can be partially applied.

Kind: static method of key

Param	Type	Description
mode	String	the relative destination
key	String	the key source

Example

key.relative('dorian', 'B major') // => 'C# dorian'
// partial application
var minor = key.relative('minor')
minor('C major') // => 'A minor'
minor('E major') // => 'C# minor'

key.tokenize(name) ⇒ Array

Split the key name into its components (pitch class tonic and mode name)

Kind: static method of key
Returns: Array - an array in the form [tonic, key]

Param	Type
name	String

Example

key.tokenize('C major') // => ['C', 'major']