Is there a way to record the audio data that's being sent to webkitAudioContext.destination
?
The data that the nodes are sending there is being played by the browser, so there should be some way to store that data into a (.wav) file.
Currently, there's not a native way to do that, but as Max said in the comment above, Recorderjs does essentially this (it doesn't chain onto the destination, but is a ScriptProcessorNode you can connect other nodes to, and have its input recorded. I built on Recorderjs to do a simple audio file recorder - https://github.com/cwilso/AudioRecorder.