Do I need to use CommonJS or AMD in Webpack 3 now?

Question

JavaScript

Or is it better to use ES6 modules?

Answer 1

Not only unnecessary, but harmful. Firstly, imports-exports are already supported by browsers and it's time to get used to good practices and a bright future :) Secondly, only es6 modules allow webpack to do tree-shaking.
Obviously you have some doubts. If you state them, the community can dispel them.