Scales

import { Scale } from "tonal";

Scale props

Scale.get

get(name: string): Scale

Get a scale from a scale name. Scale.get accepts tonics in the scale name and returns a scale type with two more properties: tonic and notes:

Scale.get("c5 pentatonic");
// =>
// {
//   empty: false,
//   name: "C5 pentatonic",
//   type: "major pentatonic",
//   tonic: "C5",
//   notes: ["C5", "D5", "E5", "G5", "A5"],
//   intervals: ["1P", "2M", "3M", "5P", "6M"],
//   aliases: ["pentatonic"],
//   setNum: 2708,
//   chroma: "101010010100",
//   normalized: "101010010100"
// }

Scale notes

Scale.degrees

degrees(scaleName: string) => (degree: number) => string

Scale.degrees returns a function to get a note name from a scale degree:

const c4major = Scale.degrees("C4 major");
c4major(1); // => "C4"
c4major(2); // => "D4"
c4major(8); // => "C5"
c4major(-1); // => "B3"
c4major(-3); // => "A3"
c4major(-7); // => "C2"

Bear in mind that degree numbers starts with 1 and 0 returns an empty string:

c4major(0); // => ""

Because it returns a function, it's handy to be used with map (and similar functions):

[1, 2, 3].map(Scale.degrees("C major")) => ["C", "D", "E"]
[1, 2, 3].map(Scale.degrees("C4 major")) => ["C4", "D4", "E4"]
[-1, -2, -3].map(Scale.degrees("C major")) => ["B", "A", "G"]

Notice that it uses octaves if the scale tonic has an octave or pitch classes (octaveless notes) otherwise.

See Chord.degrees

See https://en.wikipedia.org/wiki/Degree_(music)

Scale.steps

steps(scaleName: string) => (degree: number) => string

Same as Scale.degree but 0 is tonic. It plays better with ranges:

import { Range, Scale } from "tonal";

Range.numeric([-3, 3]).map(Scale.steps("C4 major"));
// => ["G3", "A3", "B3", "C4", "D4", "E4", "F4"]

Scale.scaleNotes

scaleNotes(notes: string[]) => string[]

Given an array of notes, return an array of sorted note names starting from the first note name of the input array.

// Always start with the first note of the input array
Scale.scaleNotes(["D4", "c#5", "A5", "F#6"]); // => ["D", "F#", "A", "C#"]
// Remove duplicates
Scale.scaleNotes(["C4", "c3", "C5", "C4", "c4"]); // => ["C"]

Scale.rangeOf

rangeOf(scaleName: string) => (from: string, to: string) => string[]

Scale.rangeOf returns a function to create scale ranges:

const range = Scale.rangeOf("C pentatonic");
range("C4", "C5"); // => ["C4", "D4", "E4", "G4", "A4", "C5"]

Please note that the scale name must have tonic:

const range = Scale.rangeOf("pentatonic");
range("C4", "C5"); // => []

This function also works with a collection of notes:

const range = Scale.rangeOf("C", "Db", "G");
range("C4", "C5"); // => ["C4", "Db4", "G4", "C5"]

Finding scales

Scale.names

names(): string[]

List all known scale names. Same as ScaleType.names()

See scale-type

Scale.detect

detect(notes: string[], options: { tonic?: string, match?: "fit" | "exact" }) => string[]

Find all scales that first a collection of notes with a given tonic:

Scale.detect(["C", "D", "E", "F", "G", "A", "B"]);
// => ["C major", "C bebop", "C bebop major",
//     "C ichikosucho",  "C chromatic"];

You can pass an optional tonic (otherwise first note will be used):

Scale.detect(["C", "D", "E", "F", "G", "A", "B"], { tonic: "A" });
// => [ 'A aeolian', 'A minor bebop', 'A chromatic' ]

You can ask just the exact match:

Scale.detect(["D", "E", "F#", "A", "B"], { match: "exact" });
// => ["D major pentatonic"]
Scale.detect(["D", "E", "F#", "A", "B"], { match: "exact", tonic: "B" });
// => ["B major pentatonic"]

Relationships

Scale.scaleChords

scaleChords(scale: string) => string[]

Get all chords that fits a given scale:

Scale.scaleChords("pentatonic");
// => ["5", "64", "M", "M6", "Madd9", "Msus2"]

Scale.extended

Scale.extended(scale: string) => string[]

Get all scales names that has the same notes and at least one more:

Scale.extended("major");
// => ["bebop", "bebop dominant", "bebop major", "chromatic", "ichikosucho"]

Scale.reduced

reduced(scale: string) => string[]

Find all scales names that are a subset of the given one (less notes but all from the given scale)

Scale.reduced("major");
// => ["ionian pentatonic", "major pentatonic", "ritusen"]

Scale.modes

modes(name: string) => string[][]

Find mode names (if any) of a given scale:

Scale.modeNames("C pentatonic"); // => [
//    ["C", "major pentatonic"],
//    ["D", "egyptian"],
//    ["E", "malkos raga"],
//    ["G", "ritusen"],
//    ["A", "minor pentatonic"]
//  ]