music-fns

music-fns is a JavaScript music utility library that contains small music notation related functions.

Installation

npm install music-fns

or

yarn add music-fns

Usage

All methods are available as named exports.

example:

import { noteToFrequency } from 'music-fns';

console.log(noteToFrequency('A4'));
// > 440

API

This is an overview of all methods & constants.

music-fns uses scientific pitch notation, you can use symbols (♭, ♯) or letters (b, #) as accidentals. The functions preserve your style (flat/sharp, letter/symbol).

Documentation is still WIP, PRs welcome.

🎵 Notes

CONSTANTS

+ NOTES

An nested array that contains a chromatic C scale with its possible note variations.

import { NOTES } from 'music-fns';

console.log(NOTES);
/* >
  [
    [ 'C', 'B#' ],
    [ 'C#', 'Db' ],
    [ 'D' ],
    [ 'D#', 'Eb' ],
    [ 'E', 'Fb' ],
    [ 'F', 'E#' ],
    [ 'F#', 'Gb' ],
    [ 'G' ],
    [ 'G#', 'Ab' ],
    [ 'A' ],
    [ 'A#', 'Bb' ],
    [ 'B', 'Cb' ]
  ]
*/

METHODS

+ getRoot(note):note

Returns the root (only note, no accidental) from a note.

import { getRoot } from 'music-fns';

console.log(getRoot('A#4'));
// > 'A'

+ getNote(note):note

Returns the full note (note + accidental) from a note.

import { getNote } from 'music-fns';

console.log(getNote('A#4'));
// > 'A#'

+ getOctave(note):?octave

Returns the octave information (or undefined) from a note.

import { getOctave } from 'music-fns';

console.log(getOctave('A#4'));
// > 4

console.log(getOctave('A#'));
// > undefined

+ getAccidental(note):?accidental

Returns the accidental (or undefined) from a note.

import { getAccidental } from 'music-fns';

console.log(getAccidental('A#4'));
// > '#'

console.log(getAccidental('A4'));
// > undefined

+ hasOctave(note):boolean

Returns true if the note has octave information.

import { hasOctave } from 'music-fns';

console.log(hasOctave('A♯4'));
// > true

console.log(hasOctave('Db'));
// > false

+ hasAccidental(note):boolean

Returns true if the note has an accidental.

import { hasAccidental } from 'music-fns';

console.log(hasAccidental('A♯4'));
// > true

console.log(hasAccidental('D'));
// > false

+ hasAccidentalLetter(note):boolean

Returns true if the note has an accidental as a letter (b, #).

import { hasAccidentalLetter } from 'music-fns';

console.log(hasAccidentalLetter('A#4'));
// > true

console.log(hasAccidentalLetter('A♯4'));
// > false

+ hasAccidentalSymbol(note):boolean

Returns true if the note has an accidental as a symbol (♭, ♯).

import { hasAccidentalSymbol } from 'music-fns';

console.log(hasAccidentalSymbol('A♯4'));
// > true

console.log(hasAccidentalSymbol('A#4'));
// > false

+ isFlat(note):boolean

Returns true if the note is flat (b, ♭).

import { isFlat } from 'music-fns';

console.log(isFlat('Gb3'));
// > true

console.log(isFlat('E♭'));
// > true

console.log(isFlat('F#3'));
// > false

+ isSharp(note):boolean

Returns true if the note is sharp (#, ♯).

import { isSharp } from 'music-fns';

console.log(isSharp('F#3'));
// > true

console.log(isSharp('A♯'));
// > true

console.log(isSharp('Gb3'));
// > false

+ isNatural(note):boolean

Returns true if the note is natural (no accidental).

import { isNatural } from 'music-fns';

console.log(isNatural('F3'));
// > true

console.log(isNatural('Gb3'));
// > false

+ flatToSharp(note):note

Converts a flat to its sharp equivalent, this function preserves the accidental style (letter or symbol). If no flat is found the function returns the unmodified input.

import { flatToSharp } from 'music-fns';

console.log(flatToSharp('Gb3'));
// > 'F#3'

+ sharpToFlat(note):note

Converts a sharp to its flat equivalent, this function preserves the accidental style (letter or symbol). If no sharp is found the function returns the unmodified input.

import { sharpToFlat } from 'music-fns';

console.log(sharpToFlat('F#3'));
// > 'Gb3'

+ areEqual(notes):boolean

Returns true if the provided notes are the same notes.

import { areEqual } from 'music-fns';

// same notes in flat & sharp, symbol and letter
console.log(areEqual(['F#3', 'Gb3', 'G♭3', 'F♯3']));
// > true

console.log(areEqual(['A3', 'F3']));
// > false

+ getChromaticCPosition(note):position

Returns the (0-indexed) position of the specific root within a chromatic C scale (equals the NOTES constant).

import { getChromaticCPosition } from 'music-fns';

console.log(getChromaticCPosition('D3'));
// > 2

console.log(getChromaticCPosition('G♯1'));
// > 8

+ haveSameOctave(notes):boolean

Returns true if all notes share the same octave information.

import { haveSameOctave } from 'music-fns';

console.log(haveSameOctave(['A3', 'D3', 'G3']));
// > true

console.log(haveSameOctave(['A#1', 'D3', 'G3']));
// > false

+ noteToFrequency(note, [options]):frequency

Converts a note to a frequency (in Hz). You can use a different base frequency for A4 via standard.

import { noteToFrequency } from 'music-fns';

console.log(noteToFrequency('A4'));
// > 440

console.log(noteToFrequency('C#3'));
// > 138.59131548843604

console.log(noteToFrequency('A4', { standard: 442 }));
// > 442

+ noteToMidi(note, [options]):midiNumber

Converts a note to its MIDI number. C4 = 60 in our implementation. You can provide a different middle C via standard.

import { noteToMidi } from 'music-fns';

console.log(noteToMidi('C4'));
// > 60

console.log(noteToMidi('A4'));
// > 81

console.log(noteToMidi('C3', { standard: 'C3' }));
// > 60

+ noteToObject(note):noteObject

Converts a note to an object describing the note.

The object can contain the following keys:

• root: a root note (C, D, E, F, G, A, B)
• [accidental]: SHARP, FLAT
• [accidentalType]: SYMBOL, LETTER
• [octave]: number

import { noteToObject } from 'music-fns';

console.log(noteToObject('A4'));
/* > {
  root: 'A',
  octave: 4
} */

console.log(noteToObject('G♯1'));
/* > {
  root: 'G',
  accidental: 'SHARP',
  accidentalType: 'SYMBOL',
  octave: 1
} */

console.log(noteToObject('Ab4'));

/* > {
  root: 'A',
  accidental: 'FLAT',
  accidentalType: 'LETTER',
  octave: 4
} */

+ objectToNote(noteObject):note

Converts an object describing the note to a note.

The object can contain following keys:

• root: a root note (C, D, E, F, G, A, B)
• [accidental]: SHARP / FLAT
• [accidentalType]: SYMBOL / LETTER
• [octave]: number

import { objectToNote } from 'music-fns';

console.log(
  objectToNote({
    root: 'A',
    octave: 4
  })
);

// > 'A4'

console.log(
  objectToNote({
    root: 'G',
    accidental: 'SHARP',
    accidentalType: 'SYMBOL',
    octave: 1
  })
);

// > 'G♯1'

+ isNote(value):boolean

Returns true if the provided value is a valid note in scientific pitch notation.

import { isNote } from 'music-fns';

console.log(isNote('A#5'));
// > true;

console.log(isNote('Q2'));
// > false;

+ accidentalToLetter(note):note

Converts a note which has an accidental as a symbol (♭, ♯) to a note with the accidental as a letter (b, #).

import { accidentalToLetter } from 'music-fns';

console.log(accidentalToLetter('A♯4'));
// > 'A#4'

+ accidentalToSymbol(note):note

Converts a note which has an accidental as a letter (b, #) to a note with the accidental as a symbol (♭, ♯).

import { accidentalToSymbol } from 'music-fns';

console.log(accidentalToSymbol('A#4'));
// > 'A♯4'

+ transferAccidental(note, referenceNote):note

Transfer the accidental type (flat or sharp) from a provided reference note

In this example, we've converted F♯3 to Gb3 because the reference note is Bb4 (a flat instead of sharp).

import { transferAccidental } from 'music-fns';

console.log(transferAccidental('F#3', 'Bb4'));
// > 'Gb3';
// = same as 'F#3', different style of notation

+ transferAccidentalStyle(note, referenceNote):note

Transfer the accidental notation style (letter or symbol) from the provided reference note

In this example, we've converted F♯3 to F♯3 because the reference note is B♭4 (a symbol instead of a letter).

import { transferAccidentalStyle } from 'music-fns';

console.log(transferAccidentalStyle('F#3', 'B♭4'));
// > 'F♯3';
// = same as 'F#3', different style of notation

+ transferStyle(note, referenceNote):note

Combination of transferAccidental and transferAccidentalStyle.

In this example, we've converted F#3 to G♭3 because the reference note is B♭4 (a flat symbol instead of a sharp letter).

import { transferStyle } from 'music-fns';

console.log(transferStyle('F#3', 'B♭4'));
// > 'G♭3';
// = same as 'F#3', different style of notation

🎹 Intervals

CONSTANTS

+ Interval

An object that contains different interval constants. Feel free to open a PR to add more interval constants.

(interval amount between the brackets ())

short:

• (0) ROOT / R
• (1) SEMITONE / S
• (2) TONE / T
• (6) TRITONE / TT
• (12) OCTAVE / O

minor / major:

• (0) PERFECT_UNISON / P1
• (1) MINOR_SECOND / m2
• (2) MAJOR_SECOND / M2
• (3) MINOR_THIRD / m3
• (4) MAJOR_THIRD / M3
• (5) PERFECT_FOURTH / P4
• (7) PERFECT_FIFTH / P5
• (8) MINOR_SIXTH / m6
• (9) MAJOR_SIXTH / M6
• (10) MINOR_SEVENTH / m7
• (11) MAJOR_SEVENTH / M7
• (12) PERFECT_OCTAVE / P8

augmented / diminished:

• (0) DIMINISHED_SECOND / d2
• (1) AUGMENTED_UNISON / A1
• (2) DIMINISHED_THIRD / d3
• (3) AUGMENTED_SECOND / A2
• (4) DIMINISHED_FOURTH / d4
• (5) AUGMENTED_THIRD / A3
• (6) DIMINISHED_FIFTH / d5
• (6) AUGMENTED_FOURTH / A4
• (7) DIMINISHED_SIXTH / d6
• (8) AUGMENTED_FIFTH / A5
• (9) DIMINISHED_SEVENTH / d7
• (10) AUGMENTED_SIXTH / A6
• (11) DIMINISHED_EIGHTH / d8
• (11) DIMINISHED_OCTAVE
• (12) AUGMENTED_SEVENTH / A7

import { Interval } from 'music-fns';

console.log(Interval.PERFECT_FOURTH);
// > 5

console.log(Interval.A6);
// > 10

console.log(Interval.MAJOR_THIRD);
// > 4

console.log(Interval.S);
// > 1

console.log(Interval.OCTAVE);
// > 12

METHODS

+ transpose(note, interval):note

Transpose a note by a specific interval (use the Interval constant). An interval can also be negative.

import { transpose, Interval } from 'music-fns';

console.log(transpose('C♯3', Interval.MAJOR_SIXTH));
// > 'A♯3'

console.log(transpose('C♯3', -Interval.O));
// > 'C♯2'

+ getIntervals(notes, [options]):intervals

Returns one or more intervals between the provided notes. You can pass fromRoot to calculate the interval from the first note (= root).

import { getIntervals } from 'music-fns';

console.log(getIntervals(['C♯3', 'A♯3']));
// > [ 9 ]

// interval 'C♯3' -> 'A♯3' and 'A♯3' -> 'B3'
console.log(getIntervals(['C♯3', 'A♯3', 'B3']));
// > [ 9, 1 ]

// interval 'C♯3' -> 'A♯3' and 'C♯3' -> 'B3'
console.log(getIntervals(['C♯3', 'A♯3', 'B3'], { fromRoot: true }));
// > [ 9, 10 ]

+ isSemitone(interval):boolean

Returns true if the interval is a semitone (1).

import { getIntervals, isSemitone } from 'music-fns';

console.log(isSemitone(getIntervals(['C♯3', 'D3'])[0]));
// > true;

+ isTone(interval):boolean

Returns true if the interval is a tone (2).

import { getIntervals, isTone } from 'music-fns';

console.log(isTone(getIntervals(['C3', 'D3'])[0]));
// > true;

+ isThird(interval):boolean

Returns true if the interval is a third (diminished, minor, major or augmented) (2, 3, 4, 5).

import { getIntervals, isThird } from 'music-fns';

console.log(isThird(getIntervals(['C4', 'E4'])[0]));
// > true;

console.log(isThird(getIntervals(['A4', 'C4'])[0]));
// > true;

console.log(isThird(getIntervals(['C4', 'E#4'])[0]));
// > true;

+ isFifth(interval):boolean

Returns true if the interval is a fifth (diminished, perfect or augmented) (6, 7, 8).

import { getIntervals, isFifth } from 'music-fns';

console.log(isFifth(getIntervals(['C4', 'G4'])[0]));
// > true;

console.log(isFifth(getIntervals(['C4', 'Gb4'])[0]));
// > true;

console.log(isFifth(getIntervals(['C4', 'G#4'])[0]));
// > true;

+ isOctave(number):boolean

Returns true if the interval is an octave (12).

import { getIntervals, isOctave } from 'music-fns';

console.log(isOctave(getIntervals(['C3', 'C4'])[0]));
// > true;

🎹 Scales & Modes

CONSTANTS

+ Scale

An object containing scale constants (array of intervals). Feel free to open PRs to add more scales.

• ALGERIAN: [ 2, 1, 2, 1, 1, 1, 3, 1 ]
• ALTERED: [ 1, 2, 1, 2, 2, 2, 2 ]
• ARABIC: [ 1, 3, 1, 2, 1, 3, 1 ]
• AUGMENTED: [ 3, 1, 3, 1, 3, 1 ]
• BALINESE: [ 1, 2, 4, 1, 4 ]
• BLUES: [ 3, 2, 1, 1, 3, 2 ]
• BYZANTINE: [ 1, 3, 1, 2, 1, 3, 1 ]
• CHINESE: [ 4, 2, 1, 4, 1 ]
• CHROMATIC: [ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ]
• DOUBLE_HARMONIC: [ 1, 3, 1, 2, 1, 3, 1 ]
• ENIGMATIC: [ 1, 3, 2, 2, 2, 1, 1 ]
• GYPSY_MAJOR: [ 1, 3, 1, 2, 1, 3, 1 ]
• HARMONIC_MINOR: [ 2, 1, 2, 2, 1, 3, 1 ]
• HIRAJOSHI: [ 1, 4, 1, 4, 2 ]
• IN_SEN: [ 1, 4, 2, 3, 2 ]
• JAPANESE: [ 1, 4, 2, 3, 2 ]
• MAJOR_PENTATONIC: [ 2, 2, 3, 2, 3 ]
• MAJOR: [ 2, 2, 1, 2, 2, 2, 1 ]
• MELODIC_MINOR: [ 2, 1, 2, 2, 2, 2, 1 ]
• MINOR_PENTATONIC: [ 3, 2, 2, 3, 2 ]
• MONGOLIAN: [ 2, 2, 3, 2, 3 ]
• NATURAL_MINOR: [ 2, 1, 2, 2, 1, 2, 2 ]
• PELOG: [ 1, 2, 4, 1, 4 ]
• PROMETHEUS: [ 2, 2, 2, 3, 1, 2 ]
• WHOLE_TONE: [ 2, 2, 2, 2, 2, 2 ]
• YO: [ 2, 3, 2, 2, 3 ]

import { Scale } from 'music-fns';

console.log(Scale.ALGERIAN);
// > [ 2, 1, 2, 1, 1, 1, 3, 1 ]

console.log(Scale.PELOG);
// > [ 1, 2, 4, 1, 4 ]

console.log(Scale.CHROMATIC);
// > [ 1, 2, 4, 1, 4 ]

+ Mode

An object containing mode constants (array of intervals). White keys on a piano from note -> note an octave up.

• IONIAN: (C - C) [ 2, 2, 1, 2, 2, 2, 1 ]
• DORIAN: (D - D) [ 2, 1, 2, 2, 2, 1, 2 ]
• PHRYGIAN: (E - E) [ 1, 2, 2, 2, 1, 2, 2 ]
• LYDIAN: (F - F) [ 2, 2, 2, 1, 2, 2, 1 ]
• MIXOLYDIAN: (G - G) [ 2, 2, 1, 2, 2, 1, 2 ]
• AEOLIAN: (A - A) [ 2, 1, 2, 2, 1, 2, 2 ]
• LOCRIAN: (B - B) [ 1, 2, 2, 1, 2, 2, 2 ]

import { Mode } from 'music-fns';

console.log(Mode.IONIAN);
// > [ 2, 2, 1, 2, 2, 2, 1 ]

console.log(Mode.MIXOLYDIAN);
// > [ 2, 2, 1, 2, 2, 1, 2 ]

METHODS

+ createScale(root, intervals, [options]):scale

Creates a scale (or mode) by providing a root note and an intervals (use the Scale or Mode constant). You can provide includeRootEnd to also include the root note transposed an octave up.

import { Scale, Mode, createScale } from 'music-fns';

console.log(createScale('C2', Scale.ARABIC));
// > [ 'C2', 'C#2', 'E2', 'F2', 'G2', 'G#2', 'B2' ]

console.log(createScale('G', Mode.MIXOLYDIAN));
// > [ 'G', 'A', 'B', 'C', 'D', 'E', 'F' ]

console.log(createScale('F2', Scale.BLUES, { includeRootEnd: true }));
// > [ 'F2', 'G#2', 'A#2', 'B2', 'C3', 'D#3', 'F3' ]

+ isScale(notes, [options]):boolean

Returns true when the array of notes is a scale.

import { isScale } from 'music-fns';

console.log(isScale(['C2', 'C#2', 'E2', 'F2', 'G2', 'G#2', 'B2']));
// > true

console.log(isScale(['C2', 'C#2', 'E4', 'F2', 'G2', 'G#2', 'C5']));
// > false

+ isMode(notes, [options]):boolean

Returns true when the provided array of notes is a mode (Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian or Locrian).

import { isMode } from 'music-fns';

console.log(isMode(['G4', 'A4', 'B4', 'C5', 'D5', 'E5', 'F5']));
// > true

console.log(isMode(['C2', 'C#2', 'E2', 'F2', 'G2', 'G#2', 'B2']));
// > false

+ isAscending(scale, [options]):boolean

Returns true if the scale is ascending.

import { isAscending } from 'music-fns';

console.log(isAscending(['C1', 'D1', 'E1', 'F1', 'G1', 'A1', 'B1', 'C2']));
// > true

console.log(isAscending(['C2', 'B1', 'A1', 'G1', 'F1', 'E1', 'D1']));
// > false

+ isDescending(scale, [options]):boolean

Returns true if the scale is descending.

import { isDescending } from 'music-fns';

console.log(isDescending(['C2', 'B1', 'A1', 'G1', 'F1', 'E1', 'D1']));
// > true

console.log(isDescending(['C1', 'D1', 'E1', 'F1', 'G1', 'A1', 'B1', 'C2']));
// > false

+ hasIntervalAmount(scale, intervalAmount, [options]):boolean

Returns true if a scale has the provided interval amount.

import { hasIntervalAmount } from 'music-fns';

console.log(hasIntervalAmount(['C2', 'C#2', 'E2', 'F2', 'G2', 'G#2', 'B2'], 7));
// > true

console.log(
  hasIntervalAmount(['C2', 'C#2', 'E2', 'F2', 'G2', 'G#2', 'B2', 'C3'], 7)
);
// > true

console.log(hasIntervalAmount(['C2', 'C#2', 'E2', 'F2', 'G2', 'G#2'], 7));
// > false

+ isPentatonic(scale, [options]):boolean

Returns true if the scale is pentatonic (5 notes per octave).

import { isPentatonic } from 'music-fns';

console.log(isPentatonic(['C', 'D', 'E', 'G', 'A']));
// > true

console.log(isPentatonic(['C', 'D', 'E', 'G', 'A', 'C']));
// > true

console.log(isPentatonic(['C', 'D', 'E', 'G']));
// > false

+ isHexatonic(scale, [options]):boolean

Returns true if the scale is hexatonic (6 notes per octave).

import { isHexatonic } from 'music-fns';

console.log(isHexatonic(['C', 'D', 'E', 'F♯', 'G♯', 'A♯']));
// > true

console.log(isHexatonic(['C', 'D', 'E', 'F♯', 'G♯', 'A♯', 'C']));
// > true

console.log(isHexatonic(['C', 'D', 'E', 'F♯', 'G♯']));
// > false

+ isHeptatonic(scale, [options]):boolean

Returns true if the scale is heptatonic (7 notes per octave).

import { isHeptatonic } from 'music-fns';

console.log(isHeptatonic(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > true

console.log(isHeptatonic(['C', 'D', 'E', 'F', 'G', 'A', 'B', 'C']));
// > true

console.log(isHeptatonic(['C', 'D', 'E', 'F', 'G', 'A']));
// > false

+ isOctatonic(scale, [options]):boolean

Returns true if the scale is octatonic (8 notes per octave).

import { isOctatonic } from 'music-fns';

console.log(isOctatonic(['D', 'E', 'F', 'G', 'A♭', 'B♭', 'B', 'C♯']));
// > true

console.log(isOctatonic(['D', 'E', 'F', 'G', 'A♭', 'B♭', 'B', 'C♯', 'D']));
// > true

console.log(isOctatonic(['D', 'E', 'F', 'G', 'A♭', 'B♭']));
// > false

+ isDiatonic(scale, [options]):boolean

Returns true if the scale is diatonic (5 tones & 2 semitones, where the semitones are separated at least 2 steps from each other).

import { isDiatonic } from 'music-fns';

console.log(isDiatonic(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > true

console.log(isDiatonic(['C', 'D', 'E', 'F#', 'G#', 'A#', 'B']));
// > false

+ isHemitonic(scale, [options]):boolean

Returns true if the scale is hemitonic (contains 1 or more semitones).

import { isHemitonic } from 'music-fns';

console.log(isHemitonic(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > true

console.log(isHemitonic(['C', 'D', 'E', 'F#', 'G#', 'A#']));
// > false

+ isAnhemitonic(scale, [options]):boolean

Returns true if the scale is anhemitonic (does not contain semitones).

import { isAnhemitonic } from 'music-fns';

console.log(isAnhemitonic(['C', 'D', 'E', 'F#', 'G#', 'A#']));
// > true

console.log(isAnhemitonic(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > false

+ isCohemitonic(scale, [options]):boolean

Returns true if the scale is cohemitonic (contains 2 or more semitones that appear consecutively in scale order).

import { isCohemitonic } from 'music-fns';

// semitones between F# - G and G - Ab
console.log(isCohemitonic(['C', 'D', 'Eb', 'F#', 'G', 'Ab', 'B', 'C']));
// > true

console.log(isCohemitonic(['C1', 'C#1', 'D#1', 'G1', 'G#1']));
// > false

+ getNoteOnDegree(scale, degree, [options]):note

Returns the note on the provided scale degree.

import { getNoteOnDegree } from 'music-fns';

console.log(getNoteOnDegree(['C1', 'D1', 'E1', 'F1', 'G1', 'A1', 'B1'], 3));
// > E1

console.log(getNoteOnDegree(['C', 'D', 'E', 'F', 'G', 'A', 'B'], 8));
// > C

+ getTonic(diatonicScale), [options]:note

Returns the note on scale degree 1 in a diatonic scale.

import { getTonic } from 'music-fns';

console.log(getTonic(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > C

+ getSupertonic(diatonicScale, [options]):note

Returns the note on scale degree 2 in a diatonic scale.

import { getSupertonic } from 'music-fns';

console.log(getSupertonic(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > D

+ getMediant(diatonicScale, [options]):note

Returns the note on scale degree 3 in a diatonic scale.

import { getMediant } from 'music-fns';

console.log(getMediant(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > E

+ getSubdominant(diatonicScale, [options]):note

Returns the note on scale degree 4 in a diatonic scale.

import { getSubdominant } from 'music-fns';

console.log(getSubdominant(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > F

+ getDominant(diatonicScale, [options]):note

Returns the note on scale degree 5 in a diatonic scale.

import { getDominant } from 'music-fns';

console.log(getDominant(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > G

+ getSubmediant(diatonicScale, [options]):note

Returns the note on scale degree 6 in a diatonic scale.

import { getLeadingTone } from 'music-fns';

console.log(getLeadingTone(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > A

+ getLeadingTone(diatonicScale, [options]):note

Returns the note on scale degree 7 in a diatonic scale.

import { getLeadingTone } from 'music-fns';

console.log(getLeadingTone(['C', 'D', 'E', 'F', 'G', 'A', 'B']));
// > B

+ normalize(scale, [options]): scale

Normalize a scale by making sure it's ascending & has a root end.

import { normalize } from 'music-fns';

console.log(normalize(['C2', 'G1', 'F1', 'E1', 'D1']));
// > ['C1', 'D1', 'E1', 'F1', 'G1', 'C2']

console.log(normalize(['C1', 'D1', 'E1', 'F1', 'G1']));
// > ['C1', 'D1', 'E1', 'F1', 'G1', 'C2']

🎹 Chords

CONSTANTS

+ Chord

An object containing chord constants (array of intervals from root, root included). Feel free to open PRs to add more chords.

• AUGMENTED: [ 0, 4, 8 ]
• DIMINISHED: [ 0, 3, 6 ]
• MAJOR_SEVENTH: [ 0, 4, 7, 11 ]
• MAJOR: [ 0, 4, 7 ]
• MINOR_MAJOR_SEVENTH: [ 0, 3, 7, 11 ]
• MINOR_SEVENTH: [ 0, 3, 7, 10 ]
• MINOR: [ 0, 3, 7 ]
• SEVENTH: [ 0, 4, 7, 10 ]

import { Chord } from 'music-fns';

console.log(Chord.MAJOR);
// > [ 0, 4, 7 ]

console.log(Chord.MINOR_MAJOR_SEVENTH);
// > [ 0, 3, 7, 11 ]

METHODS

+ createChord(root, intervals):chord

Creates a chord by providing a root note and intervals (use the Chord constant).

import { Chord, createChord } from 'music-fns';

console.log(createChord('C2', Chord.MAJOR));
// > [ 'C2', 'E2', 'G2' ]

console.log(createChord('D#3', Chord.MAJOR_SEVENTH));
// > [ 'D#3', 'G3', 'A#3', 'D4' ]

+ isTriad(chord):boolean

Returns true if the chord is a triad (a set of three notes that can be stacked in thirds).

import { isTriad } from 'music-fns';

console.log(isTriad(['F2', 'A2', 'C3']));
// > true

console.log(isTriad(['F2', 'A2', 'C3', 'D4']));
// > false

Melody

METHODS

+ createMelody(notes, pattern):notes

Creates a melody using a provided array of notes and a pattern.

import { Chord, createMelody } from 'music-fns';

console.log(createMelody(createScale('C2', Scale.MAJOR), [0, 2, 0, 1, 0, 3]));
// > [ 'C2', 'E2', 'C2', 'D2', 'C2', 'F2' ]

Thanks.

Thanks to our employer madewithlove for letting us work on this during our weekly Friyays.