Can't get loudness on Firefox

[towerofnix]

Expected behavior

When the loudness block is called and the microphone is connected, a value is returned.

Actual behavior

Nothing is returned, and an error is thrown: TypeError: this.mic.mediaStream is undefined

It looks like the error is coming from here:

Steps to reproduce

It looks like this error is spawning from this line:

// If the microphone is set up and active, measure the loudness
if (this.mic && this.mic.mediaStream.active) {

The microphone itself is set shortly before:

navigator.mediaDevices.getUserMedia({audio: true}).then(stream => {
    this.mic = this.audioContext.createMediaStreamSource(stream);

This is definitely weird, since mediaStream is defined in the WebAudio spec. Apparently a bug in Firefox. (I tested a comparable demo which uses createMediaStreamSource to take a look - yep, the mediaStream property is actually missing.)

So, browser specific. But worth looking into. I think you could just store the media stream in a separate property from this.mic:

+ this.audioStream = stream;
  this.mic = this.audioContext.createMediaStreamSource(stream);

~ if (this.mic && this.audioStream.active) {}

Operating system and browser

Firefox 58, 59. Debian (Testing).