README.md
# audio-loader
[](https://travis-ci.org/audiojs/audio-loader)
[](https://codeclimate.com/github/audiojs/audio-loader)
[](https://github.com/feross/standard)
[](https://www.npmjs.com/package/audio-loader)
[](https://greenkeeper.io/)
[](https://www.npmjs.com/package/audio-loader)
An simple and flexible audio buffer loader for browser **and node**:
```js
var load = require('audio-loader')
// load one file
load('http://example.net/audio/file.mp3').then(function (buffer) {
console.log(buffer) // => <AudioBuffer>
})
// load a collection of files
load({ snare: 'samples/snare.wav', kick: 'samples/kick.wav' },
{ from: 'http://example.net/'} ).then(function (audio) {
console.log(audio) // => { snare: <AudioBuffer>, kick: <AudioBuffer> }
})
```
## Features
- Load single audio files or collection of them (either using arrays or data objects)
- Load base64 encoded audio strings
- Compatible with midi.js pre-rendered soundfonts packages like [midi-js-soundfonts](https://github.com/gleitz/midi-js-soundfonts/tree/master/MusyngKite)
- Compatible with json encoded audio like [sampled](https://github.com/danigb/sampled)
## Install
__Npm__
`npm i --save audio-loader`
__Yarn__
`yarn add audio-loader`
__Browser__
Download the [minified distribution](https://raw.githubusercontent.com/danigb/audio-loader/master/dist/audio-loader.min.js) which exports `loadAudio` as window global:
```html
<script src="audio-loader.min.js"></script>
<script>
loadAudio({ snare: 'snare.wav' }, { from: 'oramics.github.io/sampled/' }).then(..)
</script>
```
## Usage
<a name="load"></a>
#### Load audio files
You can load individual or collection of files:
```js
load('http://path/to/file.mp3').then(function (buffer) {
// buffer is an AudioBuffer
play(buffer)
})
// apply a prefix using options.from
load(['snare.mp3', 'kick.mp3'], { from: 'http://server.com/audio/' }).then(function (buffers) {
// buffers is an array of AudioBuffers
play(buffers[0])
})
// the options.from can be a function
function toUrl (name) { return 'http://server.com/samples' + name + '?key=secret' }
load({ snare: 'snare.mp3', kick: 'kick.mp3' }, { from: toUrl }).then(function (buffers) {
// buffers is a hash of names to AudioBuffers
play(buffers['snare'])
})
```
#### Recursive loading
`audio-loader` will detect if some of the values of an object is an audio file name and try to fetch it:
```js
var inst = { name: 'piano', gain: 0.2, audio: 'samples/piano.mp3' }
load(inst).then(function (piano) {
console.log(piano.name) // => 'piano' (it's not an audio file)
console.log(piano.gain) // => 0.2 (it's not an audio file)
console.log(piano.audio) // => <AudioBuffer> (it loaded the file)
})
```
#### Load soundfont files
If you provide a `.js` file, `audio-loader` will interpret it as a [midi.js](https://github.com/mudcube/MIDI.js) soundfont file and try to load it:
```js
load('acoustic_grand_piano-ogg.js').then(function (buffers) {
buffers['C2'] // => <AudioBuffer>
})
```
This is a repository of them: https://github.com/gleitz/midi-js-soundfonts
#### API
### `load(source, [options])`
| Param | Type | Description |
| --- | --- | --- |
| source | <code>Object</code> | the object to be loaded: can be an URL string, ArrayBuffer with encoded data or an array/map of sources |
| options | <code>Object</code> | (Optional) the load options for that source |
Possible `options` keys are:
- __from__ {Function|String}: a function or string to convert from file names to urls.
If is a string it will be prefixed to the name:
`load('snare.mp3', { from: 'http://audio.net/samples/' })`
If it's a function it receives the file name and should return the url as string.
- __only__ {Array} - when loading objects, if provided, only the given keys
will be included in the decoded object:
`load('piano.json', { only: ['C2', 'D2'] })`
- __context__ {AudioContext}: (browser only) The audio context to use. By default uses [`audio-context`](https://www.npmjs.com/package/audio-context)
- __decode__ {Function}: a function to decode audio. It receives a buffer and must return a promise to an audio buffer.
- __fetch__ {Function}: a function to fetch files. It receives an url and a response type (one of 'arraybuffer' or 'text') and must return a promise to the contents
## Run tests and examples
To run the test, clone this repo and:
```bash
npm install
npm test
```
To run the browser example:
```bash
npm i -g budo
npm run browser-example
```
To run the node (audiojs) example:
```bash
node example/node.js
```
## License
MIT License