Since ES6 can be cleaner, many projects have switched to using it with a transpiler like babel. This project (if/when it works) could help move older code to the new standard for consistency.

Even otherwise, I'm sure this was a fun and challenging project for the author.

So, more like this. And congrats on release.

I agree it is a fun project.

The I'm unlikely to use a tool like this is because I find the exercise of updating the codebase manually an important. Really understanding how and why ES6 syntax can clean up your code and how to use it properly.

Also, how many times do you get such a good opportunity to re-factor everything? This is a great excuse. Make it better, not just ES6ify.

Finally, improve your regex by updating certain elements of your code. A good example is moving all var statements to let across whole codebase, and then finding cases where you can 100% use const, and replacing all of those.

I've done this update recently (as have a lot of people) and it was great. If you do it right, you should delete more code than you add, and avoid numerous bugs by using const.