Tonic.ts

Tonic.ts is a TypeScript library that provides APIs for music theory, drawing pitch constellation diagrams, and calculating guitar chord fingerings.

The API makes use of TypeScript enums, generics, and other TypeScript features. Although it can be used from straight JavaScript, there’s other alternatives (link TBD) for that.

Features

• Music theory types: Note, Interval, Chord, Scale, PitchClass. See the API documentation.
• Guitar chord calculator computes fingerings for guitar chords (and chords on other fretted instruments).
• Graphics package draw chord diagrams and pitch constellations. You can see the latter at Fingerboard.

Examples

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import { Chord, ChordQuality, Interval, Intervals, Key, Note, Scale } from 'tonic';
import { frettingFor } from 'tonic';

// Hemholtz and Scientific pitch notation
Note.fromString('C4') instanceof Note; // => true
Note.fromString('C♯4') instanceof Note; // => true
Note.fromString('C♭4') instanceof Note; // => true

// Unicode and ASCII sharps and flats
// Note.fromString('C#4') === Note.fromString('C♯4'); // => true
// Note.fromString('Cb4') === Note.fromString('C♭4'); // => true

// Enharmonic equivalents
Note.fromString('E♯4').midiNumber === Note.fromString('F4').midiNumber; // => true
Note.fromString('E4').midiNumber === Note.fromString('F♭4').midiNumber; // => true
Note.fromString('E♯4') === Note.fromString('F4'); // => false
Note.fromString('E4') === Note.fromString('F♭4'); // => false
Note.fromString('C4').octave; // => 4
Note.fromString('C4').midiNumber; // => 60
Note.fromMidiNumber(60); // ~> C4

// Intervals
Interval.fromString('M3');
Intervals.m3.semitones; // => 3
Intervals.M3.semitones; // => 4
Intervals.A3.semitones; // => 5
Intervals.d4.semitones; // => 4
Intervals.P4.semitones; // => 5
Intervals.A4.semitones; // => 6
Intervals.M3.number; // => 3
Intervals.M3.quality; // => 'M'

// Interval arithmetic
Intervals.M3.add(Intervals.m3); // ~> P5
Intervals.m3.add(Intervals.M3); // ~> P5
Intervals.m3.add(Intervals.m3); // ~> d5
Intervals.M3.add(Intervals.M3); // ~> A5

Note.fromString('C4').add(Intervals.M3); // ~> E4
Note.fromString('C4').add(Intervals.A3); // ~> E♯4
Note.fromString('C4').add(Intervals.d4); // ~> F♭4
Note.fromString('C4').add(Intervals.P4); // ~> F4

Interval.between(Note.fromString('C4'), Note.fromString('C4')); // ~> P1
Interval.between(Note.fromString('D4'), Note.fromString('C4')); // ~> M2
Interval.between(Note.fromString('E4'), Note.fromString('C4')); // ~> M3
// Interval.between(Note.fromString('E♯4'), Note.fromString('C4')); // ~> A3
// Interval.between(Note.fromString('F♭4'), Note.fromString('C4')); // ~> d4
Interval.between(Note.fromString('F4'), Note.fromString('C4')); // ~> P4

// Chords
Chord.fromString('E Major');
ChordQuality.fromString('Dominant 7th'); // ~> Dom 7th
ChordQuality.fromIntervals([Intervals.P1, Intervals.M3, Intervals.P5]); // ~> Major
ChordQuality.fromIntervals([Intervals.P1, Intervals.m3, Intervals.P5]); // ~> Minor
// ChordQuality.fromIntervals([
//   Intervals.P1,
//   Intervals.m3,
//   Intervals.P5,
//   Intervals.m7,
// ]); // => Min 7th

// Scales
const scale = Scale.fromString('Diatonic Major');
scale.intervals; // ~> [P1, M2, M3, P4, P5, M6, M7]
scale.modes; // ~> [Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian]
// scale.modes.get('Dorian').intervals; // => [P1, M2, m3, P4, P5, M6, m7]

const key = scale.at(Note.fromString('E4'));
key.intervals; // ~> [P1, M2, M3, P4, P5, M6, M7]
key.pitchClasses; // ~> [0, 2, 4, 5, 7, 9, 11]

// Instruments and fret fingerings
frettingFor('E Major')?.ascii; // ~> 022100

Status

• The API might change. In particular, FrettedChord might change back to Fingering.
• The graphics functions haven’t been tested since being ported from CoffeeScript.

Other Languages

• The original (2013) CoffeeScript version is in the coffeescript branch.
• dart-tonic is a port to Dart 2.0. It’s compatible with Flutter.

License

MIT