regex() ⇒ RegExp

A regex for matching note strings in scientific notation.

parse(note, isTonic, tunning) ⇒ Object

Parse a note name in scientific notation an return it's components, and some numeric properties including midi number and frequency.

build(obj) ⇒ String

Create a string from a parsed object or step, alteration, octave parameters

midi(note) ⇒ Integer

Get midi of a note

freq(note, tuning) ⇒ Float

Get freq of a note in hertzs (in a well tempered 440Hz A4)

A regex for matching note strings in scientific notation.

Kind: global function
Returns: RegExp - the regexp used to parse the note name

The note string should have the form letter[accidentals][octave][element] where:

• letter: (Required) is a letter from A to G either upper or lower case
• accidentals: (Optional) can be one or more b (flats), # (sharps) or x (double sharps). They can NOT be mixed.
• octave: (Optional) a positive or negative integer
• element: (Optional) additionally anything after the duration is considered to be the element name (for example: 'C2 dorian')

The executed regex contains (by array index):

• 0: the complete string
• 1: the note letter
• 2: the optional accidentals
• 3: the optional octave
• 4: the rest of the string (trimmed)
  Example

var parser = require('note-parser')
parser.regex.exec('c#4')
// => ['c#4', 'c', '#', '4', '']
parser.regex.exec('c#4 major')
// => ['c#4major', 'c', '#', '4', 'major']
parser.regex().exec('CMaj7')
// => ['CMaj7', 'C', '', '', 'Maj7']

Parse a note name in scientific notation an return it's components, and some numeric properties including midi number and frequency.

Kind: global function
Returns: Object - the parsed note name or null if not a valid note

The parsed note name object will ALWAYS contains:

• letter: the uppercase letter of the note
• acc: the accidentals of the note (only sharps or flats)
• pc: the pitch class (letter + acc)
• step: s a numeric representation of the letter. It's an integer from 0 to 6 where 0 = C, 1 = D ... 6 = B
• alt: a numeric representation of the accidentals. 0 means no alteration, positive numbers are for sharps and negative for flats
• chroma: a numeric representation of the pitch class. It's like midi for pitch classes. 0 = C, 1 = C#, 2 = D ... 11 = B. Can be used to find enharmonics since, for example, chroma of 'Cb' and 'B' are both 11

If the note has octave, the parser object will contain:

• oct: the octave number (as integer)
• midi: the midi number
• freq: the frequency (using tuning parameter as base)

If the parameter isTonic is set to true, the parsed object will contain:

• tonicOf: the rest of the string that follows note name (left and right trimmed)

Example

var parse = require('note-parser').parse
parse('Cb4')
// => { letter: 'C', acc: 'b', pc: 'Cb', step: 0, alt: -1, chroma: -1,
        oct: 4, midi: 59, freq: 246.94165062806206 }
// if no octave, no midi, no freq
parse('fx')
// => { letter: 'F', acc: '##', pc: 'F##', step: 3, alt: 2, chroma: 7 })

Create a string from a parsed object or step, alteration, octave parameters

Kind: global function
Returns: String - a note string or null if not valid parameters
Since: 1.2

Example

parser.build(parser.parse('cb2')) // => 'Cb2'

Example

// it accepts (step, alteration, octave) parameters:
parser.build(3) // => 'F'
parser.build(3, -1) // => 'Fb'
parser.build(3, -1, 4) // => 'Fb4'

Get midi of a note

Kind: global function
Returns: Integer - the midi number of the note or null if not a valid note or the note does NOT contains octave

Example

var parser = require('note-parser')
parser.midi('A4') // => 69
parser.midi('A') // => null

Example

// midi numbers are bypassed (even as strings)
parser.midi(60) // => 60
parser.midi('60') // => 60

Get freq of a note in hertzs (in a well tempered 440Hz A4)

Kind: global function
Returns: Float - the freq of the number if hertzs or null if not valid note

Example

var parser = require('note-parser')
parser.freq('A4') // => 440
parser.freq('A') // => null

Example

// can change tuning (440 by default)
parser.freq('A4', 444) // => 444
parser.freq('A3', 444) // => 222

Example

// it accepts midi numbers (as numbers and as strings)
parser.freq(69) // => 440
parser.freq('69', 442) // => 442