web-audio-instrumentation

The backbone of Web Audio Tools. Instruments methods in the Web Audio API and emits events for all activity of state.

Caveats

This library needs to maintain an internal, iterable list of AudioNodes created in the context. This means all the nodes are strongly held, and never GC'd. Obviously a big problem for complex applications, but this is mostly for debugging.

API

new WebAudioInstrumentation()

Creates a new instance of the WebAudioInstrumentation. Inherits from EventEmitter.

core.instrument(global)

Prepares the core to patch AudioContext, AudioNode and AudioParam methods. Generally, global will be the window object, but can be any object that has properties AudioContext, AudioNode and AudioParam. Must be called before any action on the Web Audio API in order to track state.

core.getNode(nodeOrID)

Takes either an AudioNode or an ID (created by the instrumentation), and returns an AudioNodeModel. This is mostly used internally.

event: "create-node"

• node: AudioNodeModel

event: "connect-node"

• source: AudioNodeModel
• dest: AudioNodeModel
• output: Number
• input: Number

event: "connect-param"

• source: AudioNodeModel
• dest: AudioNodeModel
• paramName: String
• output: Number

event: "disconnect-node"

• source: AudioNodeModel
• output: Number

event: "schedule-automation"

• node: AudioNodeModel
• paramName: String
• eventName: String
• args: Array

Example

var WebAudioInstrumentation = require("wa-tools-core");
var core = new WebAudioInstrumentation();
core.instrument(window);

core.on("create-node", (node) => {
  console.log(node.type + " created!");
});

core.on("connect-node", (source, dest, output, input) => {

});

var ctx = new AudioContext();

var osc = ctx.createOscillator();
var gain = ctx.createGain();

Build

Run gulp, as ./build/web-audio-instrumentation.js is created. If using source, requires 6to5 transformation.

Testing

Because phantomjs does not have AudioContext, run ./test/index.html in a browser. Hooray.

License

MIT License, Copyright (c) 2015 Jordan Santell