https://github.com/jsantell/allen

Utilities for the Web Audio API
https://github.com/jsantell/allen

Last synced: 3 months ago
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Utilities for the Web Audio API

• Host: GitHub
• URL: https://github.com/jsantell/allen
• Owner: jsantell
• License: mit
• Created: 2012-10-31T20:08:31.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2013-02-01T16:26:01.000Z (almost 12 years ago)
• Last Synced: 2024-10-05T22:34:53.152Z (3 months ago)
• Language: CoffeeScript
• Size: 158 KB
• Stars: 16
• Watchers: 5
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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allen

=====

[![Build Status](https://travis-ci.org/jsantell/allen.png)](https://travis-ci.org/jsantell/allen)

**allen** is a collection of utilities for the Web Audio API. As of right now, mostly type checking different objects to determine what kind of type of node an object is, but if you find yourself reusing the same methods when developing with the Web Audio API, please add them!

## Installation

Install via [npm](https://npmjs.org/), [bower](http://twitter.github.com/bower/) or [component\(1\)](https://github.com/component/component)

```

npm install allen

component install jsantell/allen

```

## Methods

### getAudioContext()

Creates and returns an available `AudioContext` for the environment. If this method was called previously, or an `AudioContext` was set via `setAudioContext()`, then the same instance will be returned.

### setAudioContext( context )

Sets the `AudioContext` to be returned from `getAudioContext()`.

### isAudioContext( node )

Returns `true` if `node` is an `AudioContext`; `false` otherwise.

### isAudioSource( node )

Returns `true` if `node` inherits from an `AudioSourceNode`, like `BufferSourceNode`, `MediaElementAudioSourceNode`, `MediaStreamAudioSourceNode` or `OscillatorNode`; `false` otherwise.

### isAudioDestination( node )

Returns `true` if `node` is an `AudioDestinationNode`; `false` otherwise.

### isAudioNode( node )

Returns `true` if `node` inherits from `AudioNode`; `false` otherwise.

### isRegularAudioNode( node )

Returns `true` if `node` inherits from `AudioNode`, and is not a source or destination node; `false` otherwise.

### isAudioParam( param )

Returns `true` if `param` inherits from `AudioParam`; `false` otherwise.

### getBuffer( url, callback, [sendImmediately] )

Sets up an XHR GET to the `url`, sets responseType to 'arraybuffer', and calls `callback` on load. If `sendImmediately` truthy, calls `send()` on the xhr object. Returns the xhr object. Used commonly with the Web Audio API.

### canPlayType( type )

Checks if the browser can play audio of `type`. Strings accepted: `'ogg'`, `'mp3'`, `'wav'`, `'m4a'`

## Example

```

  var

    ctx = allen.getAudioContext(),

    src = ctx.createMediaElementSource( new Audio() ),

    gain = ctx.createGainNode();

  allen.isAudioNode( gain );  // true

  allen.isAudioNode( src );   // true

  allen.isAudioSource( src ); // true

  allen.isAudioSource( gain ); // false

  allen.isAudioParam( gain.gain ); // true

```

## Development

Init and update git submodules and install [grunt](https://github.com/gruntjs/grunt) installed globally -- build `src` and specs and run tests with `grunt`, or fire off the watcher with `grunt watch` to build and test changes.

Run tests with `grunt mocha`. In `test/mocks/mockContext.coffee`, there is a mock AudioContext object for running tests headlessly -- tests should pass in PhantomJS, as well as browsers.