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https://github.com/danigb/note-parser
Parse notes with javascript
https://github.com/danigb/note-parser
Last synced: 9 days ago
JSON representation
Parse notes with javascript
- Host: GitHub
- URL: https://github.com/danigb/note-parser
- Owner: danigb
- License: mit
- Created: 2015-05-18T17:16:58.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2017-04-04T22:23:41.000Z (over 7 years ago)
- Last Synced: 2024-10-03T12:10:59.868Z (about 1 month ago)
- Language: JavaScript
- Size: 47.9 KB
- Stars: 55
- Watchers: 5
- Forks: 6
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG
- License: LICENSE
Awesome Lists containing this project
- awesome-javascript-audio - note-parser - Given a string, obtain a hash with note properties (including midi number and frequency) (Sound creation / Instrument recordings)
README
# note-parser [](https://www.npmjs.com/package/note-parser)
[](https://travis-ci.org/danigb/note-parser) [](https://codeclimate.com/github/danigb/note-parser)
[](https://github.com/feross/standard)
Parse note names (in [scientific notation](https://en.wikipedia.org/wiki/Scientific_pitch_notation)) with javascript. Given a string, obtain a hash
with note properties (including midi number and frequency)
If you need parse interval names take a look to [interval-notation](https://github.com/danigb/interval-notation)
## Usage
Install via npm: `npm i --save note-parser` and require it:
```js
var parser = require('note-parser')
parser.parse('c#4') // => { letter: 'C', acc: '#', ... midi: 61, freq: 277.1826309768721 }
```
The returned object will contain:
- `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 ... It can have negative values: -1 = Cb.
If the note name has octave, the returned object will additionally have:
- `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 another property is included:
- `tonicOf`: the rest of the string that follows note name (left and right trimmed)
#### Midi note number and frequency
If you are interested only in midi numbers or frequencies, you can use `midi` function:
```js
parser.midi('A4') // => 69
parser.midi('blah') // => null
parser.midi(60) // => 60
parser.midi('60') // => 60
```
or the `freq` function:
```js
parser.freq('A4') // => 440
parser.freq('A3', 444) // => 222
parser.freq(69) // => 440
```
### Build the string back
With the `build` function you can convert back to string:
```js
parser.build(parser.parse('cb2')) // => 'Cb2'
```
Alternatively the `build` function accepts `step, alteration, octave` parameters:
```js
parser.build(3, -2, 4) // => 'Fbb4'
```
## Tests and documentation
You can read the [generated API documentation here](https://github.com/danigb/note-parser/blob/master/API.md)
To run the test clone this repo and:
```
npm install
npm test
```
## License
MIT License