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https://github.com/danigb/interval-parser
Music interval parser for javascript
https://github.com/danigb/interval-parser
Last synced: 13 days ago
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Music interval parser for javascript
- Host: GitHub
- URL: https://github.com/danigb/interval-parser
- Owner: danigb
- Created: 2015-05-19T00:22:16.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2016-06-14T09:30:17.000Z (over 8 years ago)
- Last Synced: 2024-10-04T16:18:01.307Z (about 2 months ago)
- Language: JavaScript
- Size: 21.5 KB
- Stars: 6
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# interval-parser [](https://www.npmjs.com/package/interval-parser)
[](https://github.com/feross/standard) [](https://www.npmjs.com/package/interval-parser)
Parses music intervals in shorthand notation:
```js
var parser = require('interval-parser')
parser.parse('P4')
// => { num: 4, q: 'P', dir: 1, simple: 4, type: 'P', alt: 0, oct: 0, semitones: 5 }
// accepts reverse shorthand notation
parser.parse('6m')
// => { num: 6, q: 'm', dir: 1, simple: 6, type: 'M', alt: -1, oct: 0, semitones: 8 }
```
If you only need a property, you can use a function with the property name:
```js
parser.semitones('6m') // => 8
parser.simple('9M') // => 2
```
#### Interval string format
It accepts two different interval string formats:
- In standard shorthand notation: `quality+[dir]+num`. Examples: 'P8', 'M-3'
- In reverse shorthand notation: `[dur]+num+quality`. Examples: '8P', '-3M'
## API
### `parse(str)`
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
#### Parameters
* `str` **`String`** the string with the interval
#### Examples
```js
var parser = require('interval-parser')
parser.parse('P4')
// => { num: 4, q: 'P', dir: 1, simple: 4, type: 'P', alt: 0, oct: 0, semitones: 5 }
// accepts reverse shorthand notation
parser.parse('6m')
// => { num: 6, q: 'm', dir: 1, simple: 6, type: 'M', alt: -1, oct: 0, semitones: 8 }
```
Returns an object with interval properties or null if not valid interval string:
- `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.
- `semitones`: the size of the interval in semitones
### Helper functions
For each property of the interval there's a function with the same name that returns only that property:
```js
parser.num('9m') // => 9
parser.q('9m') // => 'm'
parser.simple('9m') // => 2
parser.dir('9m') // => 1
parser.type('9m') // => 'M'
parser.alt('9m') // => -1
parser.oct('9m') // => 1
parser.semitones('9m') // => 13
```
## License
MIT License