core - Documentation

This module provides functions to map scale degrees to chromatic numbers suitable for MIDI use. A few basic scales are provided as well (modes of the major scale, as well as the harmonic minor scale). You may add other scales you need to the scaleChromatics map at runtime.

Source:

core.js, line 1

Members

(static, constant) numChromatics

Source:

core.js, line 35

Number of degrees in western chromatic scale

(static, constant) origin

Source:

core.js, line 20

Determines location of middle C (default is middle C = 60)

(static, constant) scaleChromatics

Source:

core.js, line 29

Map of scale name -> chromatic degrees of scale

Example

const result = core.scaleChromatics.Ionian
// <= [0,2,4,5,7,9,11]

Methods

(static) addScale(name, degrees, relativeScale)

Source:

core.js, line 45

Add a named scale to the set of available scales

Parameters:

Name	Type	Default	Description
`name`	string		name of scale
`degrees`	Array.<(string\|number)>		list of ascending scale degrees (see `module:core.chromatic`)
`relativeScale`	string	`Ionian`	scale to which degrees are relative

(static) chromatic(degree, optionsopt) → {number}

Source:

core.js, line 77

What is the chromatic number for this scale degree?

Example

// midi note for middle C
const result = core.chromatic(1)
// <= 60

Parameters:

Name Type Attributes Description

degree

string | number

format is '[#|b]<int>', where <int> is a 1-based scale degree

options

Object

defaults are {scale='Ionian', octave=origin.octave, shift=origin.shift}

Properties

Name	Type	Attributes	Description
`scale`	string	<optional>	name of scale to use
`octave`	number	<optional>	default octave for notes with no designation
`shift`	number	<optional>	an integer used to shift the value up or down on the number line

Returns:

the chromatic number

Type: number

(static) chromatics(degrees, optionsopt) → {Array.<number>}

Source:

core.js, line 112

What are the chromatic numbers for degrees in a given scale?

Example

// midi notes for a CM7 chord
const result = core.chromatics([1, 3, 5, 7])
// <= [60,64,67,71]

Parameters:

Name	Type	Attributes	Description
`degrees`	Array.<(string\|int)>		see `module:core.chromatic`
`options`	Object	<optional>	see `module:core.chromatic`

Returns:

the chromatic numbers

Type: Array.<number>

(static) setOrigin(octave)

Source:

core.js, line 59

Sets octave which will yield middle C = 60

Parameters:

Name	Type	Description
`octave`	int	the octave for middle C