为什么 setInterval() 会给出循环引用? [英] Why does setInterval() give a circular reference?

问题描述

考虑以下代码:

let id = setInterval(function f() {console.log("Nice.");}, 1000);
console.log(id);
JSON.stringify(id);

最后一行出现错误，内容为TypeError: Converting circle structure to JSON.

This ends in an error on the last line saying TypeError: Converting circular structure to JSON.

console.log(id) 给出

Timeout {
  _called: false,
  _idleTimeout: 1000,
  _idlePrev: 
   TimersList {
     _idleNext: [Circular],
     _idlePrev: [Circular],
     _timer: Timer { '0': [Function: listOnTimeout], _list: [Circular] },
     _unrefed: false,
     msecs: 1000,
     nextTick: false },
  _idleNext: 
   TimersList {
     _idleNext: [Circular],
     _idlePrev: [Circular],
     _timer: Timer { '0': [Function: listOnTimeout], _list: [Circular] },
     _unrefed: false,
     msecs: 1000,
     nextTick: false },
  _idleStart: 81,
  _onTimeout: [Function: f],
  _timerArgs: undefined,
  _repeat: 1000,
  _destroyed: false,
  [Symbol(asyncId)]: 6,
  [Symbol(triggerAsyncId)]: 1 }

为什么 Timeout 对象包含循环引用?

Why does the Timeout object contain a circular reference?

推荐答案

请注意，setInterval 的行为不同于 setInterval.虽然 javascript 版本返回一个整数，但 node.js 返回一个 Timeout 对象. 并且是不用于序列化.

Please note, that setInterval in node.js behaves differently than setInterval in javascript. While the javascript version returns an integer, node.js returns a Timeout object. and is not intended for serialization.

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