Conditional export support

[impy88]

Hi @mourner,

thank you for the great lib!

I'm faced with the issue of using it with VITE (yet another js bundler) which is using next version of rollup behind the scene. The problem is that importing your ESM module from 3rd party modules (CJS) causes issues because of the wrong interoperability (export default doesn't work correctly in this case).

I propose to improve your lib by using conditional export, please have a look!

(I checked now it works with Vite and rollup)

Ref: https://nodejs.org/api/packages.html#packages_conditional_exports

Cheers, Maxim Kotelnikov