music-notation

music-notation

music-notation is a collection of javascript functions to parse alterations, notes, intervals and other pitched elements using different notations.

Install via npm : npm install --save music-notation

This is part of tonal

Features

• Parse notes in scientific notation
• Parse notes in helmholtz notation
• Parse intervals in short hand notation
• Parse roman numerals
• Parse pitched elements (scales, chords, keys)
• Convert accidentals to alterations and back

Notations

Fifths-octaves-duration array notation

The array notation a format to represent pitches and intervals using fifths, octaves and duration encoded as an array. It's largely based on coord notation by teoria

The array notation is the primary format in this module. All the parse functions (note/parse, interval/parse, ...) converts from string to array format. All the str functions (note/str, interval/str, ...) converts from array notation to string.

A pitch in array notation is an array with different length depending what it stores:

• 1 length array: pitch classes. It stores the number of fifths from C to the pitch class. For example: 'C' is [ 0 ], 'D' is [ 2 ], 'E' is [ 4 ], and so on.
• 2 length array: intervals. It stores the number of fifths from unison as first element, and the number of octaves up or down from that fifths. For example, [ 2, 0 ] its '9M' (major ninth) since two fifths span more than a octave, so '2M' (major second) its [ 2, -1 ]
• 3 length arrays: notes. It's the interval from C0 to the note pitch with an additional value of the duration. For example: 'C2' with no duration would be [0, 2, null].

The purpose of this design is to provide a uniform way to represent pitches (including notes, pitch classes and intervals) so lot of code can be shared, but be able to differentiate them easily.

Note scientific notation

The note scientific notation is a string with the form <letter><alteration><octave>/<duration> where only the letter is mandatory.

You can parse notes in scientific notation with note/parse:

var parse = require('music-notation/note/parse')
parse('C2') // => [0, 2, null]
parse('c2') // => [0, 2, null]

Note helmholtz notation

You can parse and build notes with strings containing note helmholtz notation

Interval shorthand notation

The interval shorthand notation is a way to encode intervals using strings. In tonal the cannonical form is <number><quality> in which the components are reversed from the standard interval shorthand notation. The reason for this is to cleary differenciate between A4 (the note) and 4A (the interval).

The interval shorthand notation parser is capable to understand the reversed and the direct interval notation as well as intervals with the form <number><alteration>:

var parse = require('music-notation/interval/parse')
parse('2M') // => [2, -1] // reverse shorthand notation (tonal's default)
parse('M2') // => [2, -1] // standard shorthand notation
parse('2') // => [2, -1] // number-alteration notation

Roman notation

The roman notation allows to express pitch classes using string with roman numerals. The cannonical form is <alteration><roman> but the parser is capable to understand the <roman><alteration> format:

var parse = require('music-notation/roman/parse')
parse('bII') // => [ -5 ] <= same as `Db`
parse('bii') // => [ -5 ] <= case is ignored
parse('IIb') // => [ -5 ] <= reversed components allowed

Accidentals

You have functions to convert accidentals string to alterations integers (### => 3, for example) and vice versa.

Usage

Read the API documentation to see all the available functions.

License

MIT License