warn about using global variables

[4www]

Really cool project!! thanks for sharing the code!

I've noticed (by importing it into my code, and having the linter run), that in the script two variables are not declared (thus used as global variables into the global scope)

• https://github.com/keithwhor/audiosynth/blob/master/audiosynth.js#L201
• https://github.com/keithwhor/audiosynth/blob/master/audiosynth.js#L210

I might be missing something, but adding let or const in front of their declaration could fix it.

Let me know, and I could open a PR if needed.

Cheers!