If you mean turning js extensions on when you import a library, then there's no way of doing it. The reason behind this, is because it could lead to security issues. What if you load a library that does some shady things that you don't know about? You'd be able to look through the code and see what the library does before it runs. And if it's loaded through src…load(), then just copy and paste that url into the browser to see the js code it runs.