Code modernization

[maciek134]

I took a look at the source code while working on #243 (comment) and I see that some of it looks old - creating classes with function and .prototype..., promises instead of async/await. If I rewrite the codebase to use more modern JS features will a PR with it be accepted?

A bit off topic, but why StandardJS? The lack of semicolons gives me shivers whenever I look at the code ;p

[alexwaibel]

Yeah, this code is using old standards and styles. At some point, I'd like to move to the Airbnb style guide and convert the whole thing to ES6 but that's a low priority task for the time being. I do find it important to modernize our style as the current standards are very difficult to read in my opinion and will deter open source contributions if we don't fix it.