Babel an Asset?

If you have a package and use api.useFiles to add assets for dynamically loading code only if and when needed on the server side (call it another level of optimized modularity if you will).
You have to use {isAssets:true} as the last argument to push them there, but if it’s a js file it’s not been run through babel for ecmaScript 6 syntax like ‘let’.

Is there (or is this a feature request) to set an option to addFiles that will process those ones through babel etc. javascript assets (and I guess other optimizations on css etc. [but I’m more concerned about javascript files])?

Alternately is there an option to addFiles to ‘server’ but not execute them as it loads?

This particular problem with ‘let’ is in part tangled up with “use strict” issues as well, but the question (aka feature request) I think is in rare cases still a valid one.