An interesting article, but I would be concerned about readability for newcomers unfamiliar with Proxies.
To be honest, for the particular use cases mentioned here - why not use the object utilities in Lodash (which is well used, familiar to many, well documented, and battle hardened)?
> we didn’t get around to implementing slices like array[1:3]
Since when? You don't need to know JS to write CSS. You just don't. You make an architectural decision, based on what you want to create, to use css-in-js. But that's a decision that you make. You can 'do' CSS without anything but... CSS!
To be honest, for the particular use cases mentioned here - why not use the object utilities in Lodash (which is well used, familiar to many, well documented, and battle hardened)?
> we didn’t get around to implementing slices like array[1:3]
What's wrong with arr.slice(1,3)?