调度定时器

Node.js 中的定时器是一种会在一段时间后调用给定函数的内部构造。 定时器函数的调用时间取决于用于创建定时器的方法以及 Node.js 事件循环正在执行的其他工作。

A timer in Node.js is an internal construct that calls a given function after a certain period of time. When a timer's function is called varies depending on which method was used to create the timer and what other work the Node.js event loop is doing.