tonal-interval

tonal-interval

tonal-interval is a collection of functions to create and manipulate music intervals.

This is part of tonal music theory library.

You can install via npm: npm i --save tonal-interval

API Reference

ivlName(ivl, the)

Get interval name. Can be used to test if it's an interval. It accepts intervals as pitch or string in shorthand notation or tonal notation. It returns always intervals in tonal notation.

semitones(ivl) ⇒ Integer

Get size in semitones of an interval

fromSemitones(num) ⇒ String

Get interval name from semitones number. Since there are several interval names for the same number, the name it's arbitraty, but deterministic.

ic(interval) ⇒ Integer

Get the interval class number of a given interval.

In musical set theory, an interval class is the shortest distance in pitch class space between two unordered pitch classes

As paramter you can pass an interval in shorthand notation, an interval in array notation or the number of semitones of the interval

itype(interval) ⇒ String

Get interval type. Can be perfectable (1, 4, 5) or majorable (2, 3, 6, 7)

invert(interval) ⇒ String | Pitch

Get the inversion#Intervals) of an interval.

simplify(interval) ⇒ String | Array

Get the simplified version of an interval.

ivlName(ivl, the)

Get interval name. Can be used to test if it's an interval. It accepts intervals as pitch or string in shorthand notation or tonal notation. It returns always intervals in tonal notation.

Kind: global function

Param	Type	Description
ivl	String | Pitch
the	String	interval name or null if not valid interval

Example

import { ivlName } from 'tonal-interval'
ivlName('m-3') // => '-3m'
ivlName('3') // => null
// part of tonal
tonal.ivlName('blah') // => null

semitones(ivl) ⇒ Integer

Get size in semitones of an interval

Kind: global function
Returns: Integer - the number of semitones or null if not an interval

Param	Type
ivl	String | Pitch

Example

import { semitones } from 'tonal-interval'
semitones('P4') // => 5
// or using tonal
tonal.semitones('P5') // => 7

fromSemitones(num) ⇒ String

Get interval name from semitones number. Since there are several interval names for the same number, the name it's arbitraty, but deterministic.

Kind: global function
Returns: String - the interval name

Param	Type	Description
num	Integer	the number of semitones (can be negative)

Example

import { fromSemitones } from 'tonal-interval'
fromSemitones(7) // => '5P'
// or using tonal
tonal.fromSemitones(-7) // => '-5P'

ic(interval) ⇒ Integer

Get the interval class number of a given interval.

In musical set theory, an interval class is the shortest distance in pitch class space between two unordered pitch classes

As paramter you can pass an interval in shorthand notation, an interval in array notation or the number of semitones of the interval

Kind: global function
Returns: Integer - A value between 0 and 6

Param	Type	Description
interval	String | Integer	the interval or the number of semitones

Example

const ic = require('interval-class')
ic('P8') // => 0
ic('m6') // => 4
['P1', 'M2', 'M3', 'P4', 'P5', 'M6', 'M7'].map(ic) // => [0, 2, 4, 5, 5, 3, 1]

itype(interval) ⇒ String

Get interval type. Can be perfectable (1, 4, 5) or majorable (2, 3, 6, 7)

Kind: global function
Returns: String - 'P' for perfectables, 'M' for majorables or null if not valid interval

Param	Type
interval	String | Pitch

Example

tonal.itype('5A') // => 'P'

invert(interval) ⇒ String | Pitch

Get the inversion of an interval.

Kind: global function
Returns: String | Pitch - the inverted interval

Param	Type	Description
interval	String | Pitch	the interval to invert in interval shorthand notation or interval array notation

Example

import { invert } from 'tonal-interval'
invert('3m') // => '6M'
// or using tonal
tonal.invert('2M') // => '7m'

simplify(interval) ⇒ String | Array

Get the simplified version of an interval.

Kind: global function
Returns: String | Array - the simplified interval

Param	Type	Description
interval	String | Array	the interval to simplify

Example

import { simplify } from 'tonal-interval'
simplify('9M') // => '2M'
['8P', '9M', '10M', '11P', '12P', '13M', '14M', '15P'].map(simplify)
// => [ '8P', '2M', '3M', '4P', '5P', '6M', '7M', '8P' ]
simplify('2M') // => '2M'
simplify('-2M') // => '7m'
// part of tonal
tonal.simplify('9m') // => '2m'