pcset

@tonaljs/pcset

Functions to create and manipulate musical pitch class sets

A pitch class set is a set (no repeated) of pitch classes (notes without octaves). Pitch classes are usefull to identify musical structures (like if two chords are related)

API

pcset(src: note[] | string | number) => Pcset

Given a collection of notes, a pitch class chroma string or a pitch class number, it returns the Pcset data object with the following attributes:

• num: the set number. Each pitch class set can be represented by an unique name between 0 and 4096. Those are the possible combinations of 12 different elements (pitch classesj)
• chroma: the set number as binary string
• intervals: the list of intervals starting from C
• length: the number of notes

Example:

pcset(["c", "d", "e"]);
// =>
// {
//   num: 2688,
//   chroma: "101010000000",
//   intervals: ["1P", "2M", "3M"],
//   length: 3
// }

It is possible to obtain the Pcset object from chroma or number:

pcset(["c", "d", "e"]) == pcset(2688);
pcset(2688) == pcset("101010000000");

isSubsetOf(parent: Set) => (subset: Set) => boolean

Test if a set is a subset of another. This function is currified

isSupersetOf(subset: Set) => (parent: Set) => boolean

Test if a set is a superset of another. This function is currified

Want more?

Take a look to @tonal/scale-dictionary or @tonal/chord-dictionary that are, in fact, dictionaries of pitch class sets.

FAQ

How do I get a list of all possible music scales?

import { chromas, pcset } from "@tonaljs/pcset";
import { transposeFrom } from "@tonaljs/note";

chromas().map(chroma => pcset(chroma).intervals.map(transposeFrom("C")));