We need a polyfill

[ajvincent]

https://github.com/zloirock/core-js/blob/master/CONTRIBUTING.md looks like a good spot (from an e-mail @Jack-Works sent me)

[ajvincent]

Maybe not. From the README for core-js:

ES Proxy can't be polyfilled, you can try to use proxy-polyfill which provides a very little subset of features.

[zloirock]

@ajvincent it does not mean that extra Proxy features like this can't be added to core-js.

Now I don't wanna add a polyfill for this proposal since now it looks raw and the API does not look stable, however, in case of stabilization, I can accept a PR.