A service like https://github.com/browserify/wzrd.in (browserify as a service), but instead of browserifying, uses babel to transpile it to es5 (or an option of environment with babel-preset-env). So, a package like whatwg-url would be installed via

# one time setup
npm config set @es5ify:registry https://es5ify.io

npm install @es5ify/whatwg-url

and scope names would remove the @ and replace the / with -- (like @angular/cli -> angular--cli, which i think is unused enough. or make the custom registry support some character that is allowed to be installed by the cli but not by the official registry (uppercase? starting with an underscore?)

Inspired by the issue seen at jsdom/whatwg-url#105