@tonaljs/pcset
v4.10.0
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Functions to work with midi numbers
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@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 useful to identify musical structures (if two chords are related, for example)
Usage
ES6:
import { Pcset } from "tonal";
nodejs:
const { Pcset } = require("tonal");
API
get(src: note[] | string | number)
Given a collection of notes, a pitch class chroma string or a pitch class number, it returns a properties 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 classes)
- chroma: the set number as binary string
- intervals: the list of intervals starting from C
- length: the number of notes
Example:
Pcset.get(["c", "d", "e"]);
// =>
// {
// num: 2688,
// chroma: "101010000000",
// intervals: ["1P", "2M", "3M"],
// length: 3
// }
It is possible to obtain the properties from chroma or set number. All this function calls returns the same object:
Pcset.get(["c", "d", "e"]);
Pcset.get(2688);
Pcset.get("101010000000");
Several shorthands (num
, chroma
, intervals`) are provided:
Pcset.chroma(["c", "d", "e"]); //=> "101010000000"
Pcset.num(["c", "d", "e"]); //=> 2192
// several set representations are accepted
Pcset.chroma(2192); //=> "101010000000"
Pcset.num("101010000000"); // => 2192
Intervals are always calculated from C
:
Pcset.intervals(["c", "d", "e"]); // => ["1P", "5P", "7M"]
Pcset.intervals(["D", "F", "A"]); // => ["2M", "4P", "6M"]
notes(pcset: string | number | string[]) => string[]
Given a pcset or a list of notes, it returns the sorted pitch class notes:
Pcset.notes(["D3", "A3", "Bb3", "C4", "D4", "E4", "F4", "G4", "A4"]); // => ["C", "D", "E", "F", "G", "A", "Bb"]
Pcset.notes("101011010110"); // => ["C", "D", "E", "F", "G", "A", "Bb"]
isIncludedIn(parent: Set) => (note: string) => boolean
Test if a note is included in the given set. This function is currified:
const isInCTriad = isNoteIncludedIn(["C", "E", "G"]);
isInCTriad("C4"); // => true
isInCTriad("C#4"); // => false
Keep in mind that enharmonics are included:
isInCTriad("Fb"); // => true
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-type or @tonal/chord-type 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")));