tonal-notation

tonal-notation

tonal-notation is a collection of functions to create and manipulate strings with music information.

This is part of tonal music theory library.

You can install via npm: npm i --save tonal-notation

API Reference

toStep(letter) ⇒ Integer

Given a letter, return step

isStep(step) ⇒ Boolean

Test if a number is a valid step number (a number from 0 to 6)

toLetter(step) ⇒ String

Given a step, return a letter

areFlats(str) ⇒ Boolean

Test if a string are all flats (b) chars

areSharps(str) ⇒ Boolean

Test if a string are all sharps (#) chars

toAlt(accidentals) ⇒ Integer

Given an accidentals string return its alteration, the number of semitones (positive for sharps, negative for flats, 0 for none)

toAcc(alteration) ⇒ String

Given an alteration number, returns the accidentals string

toStep(letter) ⇒ Integer

Given a letter, return step

Returns: Integer - the step number (from 0 to 6)

Param	Type	Description
letter	String	the letter

isStep(step) ⇒ Boolean

Test if a number is a valid step number (a number from 0 to 6)

Returns: Boolean - true if it's a valid step number, false otherwise

Param	Type	Description
step	Integer	the step number

toLetter(step) ⇒ String

Given a step, return a letter

Returns: String - the note letter or null if not valid step number

Param	Type	Description
step	Integer	the step number

areFlats(str) ⇒ Boolean

Test if a string are all flats (b) chars

Returns: Boolean - true if all charaters are b, false otherwise

Param	Type	Description
str	String	the string to test

areSharps(str) ⇒ Boolean

Test if a string are all sharps (#) chars

Returns: Boolean - true if all charaters are #, false otherwise

Param	Type	Description
str	String	the string to test

toAlt(accidentals) ⇒ Integer

Given an accidentals string return its alteration, the number of semitones (positive for sharps, negative for flats, 0 for none)

Returns: Integer - the alteration number of null if not a valid accidental strings

Param	Type	Description
accidentals	String	the string to parse

Example

toAlt('###') // => 3
toAlt('bbb') // => -3

toAcc(alteration) ⇒ String

Given an alteration number, returns the accidentals string

Returns: String - the accidental string

Param	Type	Description
alteration	Integer	the number of semitones (positive and negative values are accepted for sharps and flats)

Example

toAcc(3) // => '###'
toAcc(-3) // => 'bbb'