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) // =>
})

// 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: , kick: }
})
`

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
- Compatible with json encoded audio like sampled

Install

__Npm__

Via npm: npm i --save audio-loader

__Browser__

Download the minified distribution (4kb) which exports loadAudio as window global:

`html


`

Usage

#### 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) // => (it loaded the file)
})
`

#### Load soundfont files

If you provide a .js file, audio-loader will interpret it as a midi.js soundfont file and try to load it:

`js
load('acoustic_grand_piano-ogg.js').then(function (buffers) {
buffers['C2'] // =>
})
`

This is a repository of them: https://github.com/gleitz/midi-js-soundfonts

#### API

$3

| Param | Type | Description |
| --- | --- | --- |
| source | Object | the object to be loaded: can be an URL string, ArrayBuffer with encoded data or an array/map of sources |
| options | Object | (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
- __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 example-browser
`

To run the node (audiojs) example:

`bash
node example/node.js
``

License

MIT License