对象的深拷贝

const isComplexDataType = (obj) =>
  (typeof obj === 'object' || typeof obj === 'function') && obj !== null;

const deepClone = (obj, hash = new WeakMap()) => {
  if (obj.constructor === Date) return new Date(obj);
  if (obj.constructor === RegExp) return new RegExp(obj);
  if (hash.has(obj)) return hash.get(obj);

  let allDesc = Object.getOwnPropertyDescriptors(obj); //遍历传入参数所有键的特性
  let cloneObj = Object.create(Object.getPrototypeOf(obj), allDesc); //继承原型链

  hash.set(obj, cloneObj);

  for (let key of Reflect.ownKeys(obj)) {
    //Reflect.ownKeys(obj)可以拷贝不可枚举属性和符号类型
    // 如果值是引用类型(非函数)则递归调用deepClone
    cloneObj[key] =
      isComplexDataType(obj[key]) && typeof obj[key] !== 'function'
        ? deepClone(obj[key], hash)
        : obj[key];
  }
  return cloneObj;
};
let obj = {
  num: 0,
  str: '',
  boolean: true,
  unf: undefined,
  nul: null,
  obj: {
    name: '我是一个对象',
    id: 1,
  },
  arr: [0, { name: 'wang' }, 2],
  func: function () {
    console.log('我是一个函数');
  },
  date: new Date(0),
  reg: new RegExp('/我是一个正则/ig'),
  [Symbol('1')]: 1,
};

Object.defineProperty(obj, 'innumerable', {
  enumerable: false,
  value: '不可枚举属性',
});
obj = Object.create(obj, Object.getOwnPropertyDescriptors(obj));
obj.loop = obj;
let cloneObj = deepClone(obj);
console.log('obj', obj);
console.log('cloneObj', cloneObj);
for (let key of Object.keys(cloneObj)) {
  if (
    typeof cloneObj[key] === 'object' ||
    typeof cloneObj[key] === 'function'
  ) {
    console.log(`${key}相同吗？ `, cloneObj[key] === obj[key]);
  }
}

参考链接:
https://juejin.cn/post/6844903749270372365#
https://juejin.cn/post/7134970746580762637#