[jewel]

Would it work to have the data structures be copy-on-write? That way if the worker only reads then it's O(1), you just pass a reference to the worker.

I imagine it'd be a pain to write a garbage collector for something like that.

[benjaminjackman]

Copy on write is already implemented-ish with transferable objects [1] (just copy then write the copy).

However, copy on write still requires allocation and for some applications that is a deal breaker.

1: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers...