JavaScript 深拷贝的循环引用问题详解

let obj = { name: 'liaoyi',age: 22,sex: 1}
JSON.parse(JSON.stringify(obj))

let obj = { name: 'liaoyi',age: 22,sex: 1}
JSON.parse(JSON.stringify(obj))
obj.c = obj
console.log(JSON.stringify(obj))

function deepClone(obj) {
  const objectMap = new Map();
  const _deepClone = value => {
    const type = typeof value;
    if (type !== 'object' || type === null) {
      return value;
    }
    if (objectMap.has(value)) {
      return objectMap.get(value);
    }
    const result = Array.isArray(value) ? [] : {};

    objectMap.set(value, result);

    for (const [key, _v] of Object.entries(value)) {
      result[key] = _deepClone(value[key]);
      console.log(key, _v);
    }
    return result;
  };
  return _deepClone(obj);
}

// 通过这个构造函数，创建一个消息通道，它会返回一个对象,解构 port1, port2 来实现通信
const { port1, port2 } = new MessageChannel();
port1.postMessage('hello')
port2.onmessage = msg => {
  console.log(msg.data)  // hello
}

 function deepClone(obj) {
  return new Promise(resolve => {
    const { port1, port2 } = new MessageChannel();
    port1.postMessage(obj);

    port2.onmessage = msg => {
      resolve(msg.data);
      // console.log(obj, msg.data === obj); // false
    };
  })
}

 const obj = { a: 1, b: '2' }
 obj.c = obj; 
 deepClone(obj).then(res =>{
  console.log('res',res);
 })