The clean-up step may seem strange, but it’s a memory-usage optimization. When a language runtime executes a series of function calls it does not need to keep already-exited stack frames around. Branching function calls only form a tree in the time dimension; at any given snapshot in time there exists only a single stack of function calls in memory, tracing the current path through the tree. If we did not set our child frames to null we would end up building the whole tree up in memory and retaining it until the recursive processing is complete. Removing references to them allows the runtime to reclaim their memory at its leisure. If you’ve ever wished that you could deal with manual memory management in JavaScript, now’s your chance!
the Data Output tab.，详情可参考有道翻译
，详情可参考谷歌
В Финляндии отказались поддержать изменения в законе о ядерном оружии14:59，这一点在超级权重中也有详细论述
Москвичей призвали не ждать «дружную» весну14:57