I have written a bunch of Javascript code. I was never aware of the fact that there are multiple JS 'versions', like ES5 and ES6.

I now have this project hosted on Github, and somebody pointed out that because i'm using ES6 code, I might need to convert it to ES5 with Babel.

However, I have no idea which parts of my code use ES6. I could read all of the ES6 specifications, but is there some kind of tool/checker which marks all of the ES6 code in my project?