text: //  浅拷贝
  const shadowCopy = (obj) => {
    if (obj === null || typeof obj !== 'object') return obj
  
    let res = obj instanceof Array ? [] : {}
    for (let key in obj) {
      res[key] = obj[key]
    }
    return res
  }
  
  // 深拷贝
  const deepCopy = (obj) => {
    // 默认类型的
    if (obj === null || typeof obj !== 'object') return obj
    const res = obj instanceof Array ? [] : {}
    for (let key in obj) {
      if (obj.hasOwnProperty(key)) {
        res[key] = typeof obj[key] === 'object' ? deepCopy(obj[key]) : obj[key]
      }
    }
    return res
  }
  