This isn't an uncollectable reference cycle. It's true that with this code in most/all JS engines, if there's a reference to the function `longLived` then `larg

This isn't an uncollectable reference cycle. It's true that with this code in most/all JS engines, if there's a reference to the function `longLived` then `largeObject` will be kept in memory, but reference cycles are collectable in standard garbage collection systems. Both of the values will be garbage-collectable once no outside references to `longLived` still exist. Pure reference counting systems (Rust Rc, C++ shared_ptr, etc) are the kind of system that fail to automatically handle cycles. You could test this with your code by setting a FinalizationRegistry to log when they're both finalized, unset any outside reference to `longLived`, and then do something to force a GC (like run Node with --expose-gc and call `global.gc()`, or just allocate a big Uint8Array).