Converting a JS object to a void pointer as an opaque value and back

[anyc]

Hello,

the C library I use offers the possibility to register an arbitrary void pointer as "userdata" with an opaque structure (lib_set_userdata()). If an event occurs, a generic callback function is called with the opaque structure as argument and I can retrieve the userdata from the structure using another function (lib_get_userdata()).

I currently fail to come up with a solution to pass an arbitrary JS object as void pointer and convert it back to the same object in the callback function. Is this somehow supported with Koffi? I guess, I could maintain my own list of userdata objects in a list and store the index in the void pointer and use the index later to convert it back to the object.

I saw that I could bind a callback function to an object with koffi.register() but in my case, the callback is generic and I need to reconstruct the JS object from a void pointer.

Thank you!