Figure out which browsers to support on which features: https://kangax.github.io/compat-table/es6/
Have an alternate .babelrc with a transpile blacklist that points to a separate dest
Build a regex to match those browsers in your CDN (I use Fastly). Vary on the value you create.
Point said browsers asking for the normal JS payload to the alternate dest.
Figure out which browsers to support on which features: https://kangax.github.io/compat-table/es6/
Have an alternate .babelrc with a transpile blacklist that points to a separate dest
Build a regex to match those browsers in your CDN (I use Fastly). Vary on the value you create.
Point said browsers asking for the normal JS payload to the alternate dest.