feat: allow thunked objects to be spreadable

[monotykamary]

Arrays returned in thunks can concatenated with the spread operator while objects cannot. This adds traps for ownKeys and getOwnPropertyDescriptor on ThunkProxy to allow non-iterable objects to be spreadable.

[ivenmarquardt]

Thanks for contributing! Spreadable thunked objects are useful, of course. However, before I merge this branch I have to take a closer look at your getOwnPropertyDescriptor trap, because it seems to convert every property to be an enumerable/configurable one, even if the wrapped object has non-enumerable ones. Maybe I am just confusing things, so please bear with me..

[monotykamary]

because it seems to convert every property to be an enumerable/configurable one, even if the wrapped object has non-enumerable ones

Oh, you're right. In that case, we can reflect the getOwnPropertyDescriptor to preserve descriptors.

I've pushed a new commit to 'reflect' this 😅. It will throw a TypeError if the proxy object is not configurable, which I haven't thought up a clean solution for 🤔.

[ivenmarquardt]

Looks good, thanks!