I am not using Laravel elixir/mix for long time, tired of slow development, kinda bad design and noway to contribute to it.
Setting babel alone is also a huge pain.
So I created a Bunny Assets builder which just works. It settings defaults to Laravel and it can be used to replace Laravel Mix easily.
Just follow basic steps in Installation and run node build js index -p (for resources/assets/js/index.js file, for example, and add -p if you need compressed production version as well).
If you need only to convert basic syntax, you are done here, if not, you, probably, will need to include also babel helpers.