tonal-pcset

PcSet

tonal-pcset is a collection of functions to work with pitch class sets, oriented to make comparations (isEqual, isSubset, isSuperset)

This is part of tonal music theory library.

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

// es6
import PcSet from "tonal-pcset"
var PcSet = require("tonal-pcset")

PcSet.isEqual("c2 d5 e6", "c6 e3 d1") // => true

API documentation

• PcSet
  • .chroma(set) ⇒ String
  • .chromas() ⇒ Array
  • .modes(set, normalize) ⇒ Array.<String>
  • .isChroma(chroma) ⇒ Boolean
  • .intervals(pcset) ⇒ Array
  • .isEqual(set1, set2) ⇒ Boolean
  • .isSubsetOf(set, notes) ⇒ boolean
  • .isSupersetOf(set, notes) ⇒ boolean
  • .includes(set, note) ⇒ Boolean
  • .filter(set, notes) ⇒ Array

PcSet.chroma(set) ⇒ String

Get chroma of a pitch class set. A chroma identifies each set uniquely. It"s a 12-digit binary each presenting one semitone of the octave.

Note that this function accepts a chroma as parameter and return it without modification.

Kind: static method of PcSet
Returns: String - a binary representation of the pitch class set

Param	Type	Description
set	Array | String	the pitch class set

Example

PcSet.chroma(["C", "D", "E"]) // => "1010100000000"

PcSet.chromas() ⇒ Array

Get a list of all possible chromas (all possible scales) More information: http://allthescales.org/

Kind: static method of PcSet
Returns: Array - an array of possible chromas from '10000000000' to '11111111111'

PcSet.modes(set, normalize) ⇒ Array.<String>

Given a a list of notes or a pcset chroma, produce the rotations of the chroma discarding the ones that starts with "0"

This is used, for example, to get all the modes of a scale.

Kind: static method of PcSet
Returns: Array.<String> - an array with all the modes of the chroma

Param	Type	Description
set	Array | String	the list of notes or pitchChr of the set
normalize	Boolean	(Optional, true by default) remove all the rotations that starts with "0"

Example

PcSet.modes(["C", "D", "E"]).map(PcSet.intervals)

PcSet.isChroma(chroma) ⇒ Boolean

Test if the given string is a pitch class set chroma.

Kind: static method of PcSet
Returns: Boolean - true if its a valid pcset chroma

Param	Type	Description
chroma	String	the pitch class set chroma

Example

PcSet.isChroma("101010101010") // => true
PcSet.isChroma("101001") // => false

PcSet.intervals(pcset) ⇒ Array

Given a pcset (notes or chroma) return it"s intervals

Kind: static method of PcSet
Returns: Array - intervals or empty array if not valid pcset

Param	Type	Description
pcset	String | Array	the pitch class set (notes or chroma)

Example

PcSet.intervals("1010100000000") => ["1P", "2M", "3M"]

PcSet.isEqual(set1, set2) ⇒ Boolean

Test if two pitch class sets are identical

Kind: static method of PcSet
Returns: Boolean - true if they are equal

Param	Type	Description
set1	Array | String	one of the pitch class sets
set2	Array | String	the other pitch class set

Example

PcSet.isEqual(["c2", "d3"], ["c5", "d2"]) // => true

PcSet.isSubsetOf(set, notes) ⇒ boolean

Create a function that test if a collection of notes is a subset of a given set

The function can be partially applied

Kind: static method of PcSet
Returns: boolean - true if notes is a subset of set, false otherwise

Param	Type	Description
set	Array | String	an array of notes or a chroma set string to test against
notes	Array | String	an array of notes or a chroma set

Example

const inCMajor = PcSet.isSubsetOf(["C", "E", "G"])
inCMajor(["e6", "c4"]) // => true
inCMajor(["e6", "c4", "d3"]) // => false

PcSet.isSupersetOf(set, notes) ⇒ boolean

Create a function that test if a collectio of notes is a superset of a given set (it contains all notes and at least one more)

Kind: static method of PcSet
Returns: boolean - true if notes is a superset of set, false otherwise

Param	Type	Description
set	Array | String	an array of notes or a chroma set string to test against
notes	Array | String	an array of notes or a chroma set

Example

const extendsCMajor = PcSet.isSupersetOf(["C", "E", "G"])
extendsCMajor(["e6", "a", "c4", "g2"]) // => true
extendsCMajor(["c6", "e4", "g3"]) // => false

PcSet.includes(set, note) ⇒ Boolean

Test if a given pitch class set includes a note

Kind: static method of PcSet
Returns: Boolean - true if the note is included in the pcset

Param	Type	Description
set	Array | String	the base set to test against
note	String | Pitch	the note to test

Example

PcSet.includes(["C", "D", "E"], "C4") // => true
PcSet.includes(["C", "D", "E"], "C#4") // => false

PcSet.filter(set, notes) ⇒ Array

Filter a list with a pitch class set

Kind: static method of PcSet
Returns: Array - the filtered notes

Param	Type	Description
set	Array | String	the pitch class set notes
notes	Array | String	the note list to be filtered

Example

PcSet.filter(["C", "D", "E"], ["c2", "c#2", "d2", "c3", "c#3", "d3"]) // => [ "c2", "d2", "c3", "d3" ])
PcSet.filter(["C2"], ["c2", "c#2", "d2", "c3", "c#3", "d3"]) // => [ "c2", "c3" ])