Manual Nulling vs. Mark-and-Sweep: Trade‑off for Closure Memory Reclamation

Goal: assess whether explicitly nulling a reference captured by a closure yields earlier memory reclamation than relying solely on the engine’s Mark‑and‑Sweep garbage collector.

Constraint: modern JavaScript engines employ generational GC and may optimize short‑lived objects, making the impact of manual nulling unclear; additionally, WeakMap/WeakSet offer alternative ways to avoid retaining large values, introducing a trade‑off between developer effort and potential performance gain.

Questions: Does setting a captured variable to null reduce the retained heap size of a long‑lived closure compared to leaving it untouched? Does the observable benefit differ between engine versions or depend on the object’s lifetime in the young versus old generation? Are there cases where manual nulling adds measurable overhead without improving GC reclamation?