pitch-op

Music pitch operator is a fast and low level library to manipulate pitches or intervals in pitch-array format.

Probably you wanto to use a higher level library:

• pitch-transpose: transpose pitches
• music-gamut: work with groups of notes or intervals
• music-scale: music scales made easy
• music-chord: music chords library

API

add(a, b) → {Array}

Add two pitches or intervals. Can be used to tranpose pitches.

Parameters:

Name	Type	Description
a	Array	one pitch or interval in pitch-array format
b	Array	the other pitch or interval in pitch-array format

Source:

• index.js , lineno 118

Returns:

both pitches or intervals added in pitch-array format

Type

Array

Example

var op = require('pitch-op')
op.add([3, 0, 0], [4, 0, 0]) // => [0, 0, 1]

comparator(descending) → {function}

Get a comparator to sort pitches by height (frequency)

Parameters:

Name	Type	Description
descending	Boolean	set to true if want a descending comparator

Source:

• index.js , lineno 91

Returns:

the comparator function

Type

function

Example

arrayOfPitches.sort(op.comparator())

multiply(n, a) → {Array}

Multiply a pitch or interval by a scalar

Parameters:

Name	Type	Description
n	Array	the scalar
a	Array	the pitch or interval in pitch-array format

Source:

• index.js , lineno 151

Returns:

the pitch or interval multiplied in pitch-array format

Type

Array

Example

var op = require('pitch-op')
op.multiply(2, [4, 0, 0]) // => [1, 0, 1]

pitchClass(pitch) → {Array}

Get pitch class of a pitch.

Parameters:

Name	Type	Description
pitch	Array	the pitch

Source:

• index.js , lineno 9

Returns:

the pitch class of the pitch

Type

Array

Example

pitchClass([1, -2, 3]) // => [1, -2, nul]

semitones(pitch) → {Integer}

Get distance in semitones from [0, 0, 0] ('C0' or '1P')

Parameters:

Name	Type	Description
pitch	Array	the pitch or interval

Source:

• index.js , lineno 77

Returns:

the distance

Type

Integer

Example

op.semitones([1, 1, 0]) // => 3
op.semitones([0, 0, 0]) // => 0

setDefaultOctave(octave, pitch)

Set the octave only if not present

This function can be partially applied (Integer -> Array -> Array)

Parameters:

Name	Type	Description
octave	Integer	the octave number
pitch	Array	the pitch

Source:

• index.js , lineno 56

Example

op.setDefaultOctave(1, [1, 2, null]) // => [1, 2, 1]
op.setDefaultOctave(1, [1, 2, 3]) // => [1, 2, 3]
// partially applied:
arrayOfPitches.map(op.setDefaultOctave(3))

setOctave(octave, pitch) → {Array}

Set octave of a pitch.

This function can be partially applied (Integer -> Array -> Array)

Parameters:

Name	Type	Description
octave	Integer	the octave to set
pitch	Array	the pitch

Source:

• index.js , lineno 22

Returns:

the pitch with the given octave

Type

Array

Example

setOctave(2, [1, 2, 0]) // => [1, 2, 2]
// partially applied, you get a function:
arrayOfPitchs.map(setOctave(2))

simplify(interval) → {Array}

Simplify interval (set the octave to 0)

Parameters:

Name	Type	Description
interval	Array	the interval

Source:

• index.js , lineno 43

Returns:

the simplified interval

Type

Array

Example

op.simplify([1, 2, 3]) // => [1, 2, 0]

subtract(a, b) → {Array}

Subtract two pitches or intervals. Can be used to find the distance between pitches.

Parameters:

Name	Type	Description
a	Array	one pitch or interval in pitch-array format
b	Array	the other pitch or interval in pitch-array format

Source:

• index.js , lineno 128

Returns:

both pitches or intervals substracted pitch-array format

Type

Array

Example

var op = require('pitch-op')
op.subtract([4, 0, 0], [3, 0, 0]) // => [1, 0, 0]

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License

MIT License