API.md

Functions

parse(str, strict) ⇒ Object

Parse a string with an interval in shorthand notation (https://en.wikipedia.org/wiki/Interval_(music)#Shorthand_notation) and returns an object with interval properties.

type(num) ⇒ String

Get the type of interval. Can be perfectavle ('P') or majorable ('M')

shorthand(simple, alt, oct, dir)

Build a shorthand interval notation string from properties.

build(simple, alt, oct, dir)

Build a special shorthand interval notation string from properties. The special shorthand interval notation changes the order or the standard shorthand notation so instead of 'M-3' it returns '-3M'.

The standard shorthand notation has a string 'A4' (augmented four) that can't be differenciate from 'A4' (the A note in 4th octave), so the purpose of this notation is avoid collisions

qToAlt(num, quality) ⇒ Integer

Get an alteration number from an interval quality string. It accepts the standard dmMPA but also sharps and flats.

altToQ(num, alt) ⇒ String

Get interval quality from interval type and alteration

parse(str, strict) ⇒ Object

Parse a string with an interval in shorthand notation (https://en.wikipedia.org/wiki/Interval_(music)#Shorthand_notation) and returns an object with interval properties.

Kind: global function
Returns: Object - an object properties or null if not valid interval string The returned object contains:

• num: the interval number
• q: the interval quality string (M is major, m is minor, P is perfect...)
• simple: the simplified number (from 1 to 7)
• dir: the interval direction (1 ascending, -1 descending)
• type: the interval type (P is perfectable, M is majorable)
• alt: the alteration, a numeric representation of the quality
• oct: the number of octaves the interval spans. 0 for simple intervals.
• size: the size of the interval in semitones

Param	Type	Description
str	String	the string with the interval
strict	Boolean	(Optional) if its false, it doesn't check if the interval is valid or not. For example, parse('P2') returns null (because a perfect second is not a valid interval), but parse('P2', false) it returns { num: 2, dir: 1, q: 'P'... }

Example

var parse = require('interval-notation').parse
parse('M3')
// => { num: 3, q: 'M', dir: 1, simple: 3,
//      type: 'M', alt: 0, oct: 0, size: 4 }

type(num) ⇒ String

Get the type of interval. Can be perfectavle ('P') or majorable ('M')

Kind: global function
Returns: String - P if it's perfectable, M if it's majorable.

Param	Type	Description
num	Integer	the interval number

shorthand(simple, alt, oct, dir)

Build a shorthand interval notation string from properties.

Kind: global function

Param	Type	Description
simple	Integer	the interval simple number (from 1 to 7)
alt	Integer	the quality expressed in numbers. 0 means perfect or major, depending of the interval number.
oct	Integer	the number of octaves the interval spans. 0 por simple intervals. Positive number.
dir	Integer	the interval direction: 1 ascending, -1 descending.

Example

var interval = require('interval-notation')
interval.shorthand(3, 0, 0, 1) // => 'M3'
interval.shorthand(3, -1, 0, -1) // => 'm-3'
interval.shorthand(3, 1, 1, 1) // => 'A10'

build(simple, alt, oct, dir)

Build a special shorthand interval notation string from properties. The special shorthand interval notation changes the order or the standard shorthand notation so instead of 'M-3' it returns '-3M'.

The standard shorthand notation has a string 'A4' (augmented four) that can't be differenciate from 'A4' (the A note in 4th octave), so the purpose of this notation is avoid collisions

Kind: global function

Param	Type	Description
simple	Integer	the interval simple number (from 1 to 7)
alt	Integer	the quality expressed in numbers. 0 means perfect or major, depending of the interval number.
oct	Integer	the number of octaves the interval spans. 0 por simple intervals. Positive number.
dir	Integer	the interval direction: 1 ascending, -1 descending.

Example

var interval = require('interval-notation')
interval.build(3, 0, 0, 1) // => '3M'
interval.build(3, -1, 0, -1) // => '-3m'
interval.build(3, 1, 1, 1) // => '10A'

qToAlt(num, quality) ⇒ Integer

Get an alteration number from an interval quality string. It accepts the standard dmMPA but also sharps and flats.

Kind: global function
Returns: Integer - the interval alteration

Param	Type	Description
num	Integer | String	the interval number or a string representing the interval type ('P' or 'M')
quality	String	the quality string

Example

qToAlt('M', 'm') // => -1 (for majorables, 'm' is -1)
qToAlt('P', 'A') // => 1 (for perfectables, 'A' means 1)
qToAlt('M', 'P') // => null (majorables can't be perfect)

altToQ(num, alt) ⇒ String

Get interval quality from interval type and alteration

Kind: global function
Returns: String - the quality string

Param	Type	Description
num	Integer | String	the interval number of the the interval type ('M' for majorables, 'P' for perfectables)
alt	Integer	the interval alteration

Example

altToQ('M', 0) // => 'M'