Thanks for the feedback. I’ll try to go through the script and change occurrences. I was not aware that javascript did weird type coercion if you use double equals, (I actually only used triple equals at some point because my code editor yelled at me, I should probably have looked it up then.)
I changed the code as per your suggestions. 
At first I thought I would use the async/await functions, but I actually found I didn’t need them. I’m not sure I really needed to use the newer JS keywords, but considering this script is mostly for Chrome and Firefox users, I don’t think I’ll need to worry about compatibility, and the fat arrows are very concise.
EDIT 2: Did some more changes to improve readability and clean up some debugging code. Also changed the config id because it seems like there might be collisions if I use the default value. This may mean anyone who installed the script and updated now needs to enter their API key again, sorry about that.