原生实现深度拷贝函数

function typeIs(data) {
  if (!data) return typeof data
  return data.constructor.name
}
function deepClone (data,cache = new WeakMap()) {
   if (!data || typeof data !== 'object' || typeIs(data) === 'Date' || typeIs(data) === 'RegExp') return data
   if (cache.get(data)) {
     return cache.get(data)
   }
   if (typeIs(data) === 'Set') {
     let temp = new Set()
     cache.set(data,temp)
     for (let v of data) {
        temp.add(deepClone(v,cache))
     }
     return temp
   }
   if (typeIs(data) === 'Map') {
     let temp = new Map()
     cache.set(data,temp)
     for (let [key,v] of data) {
        temp.set(key,deepClone(v,cache))
     }
     return temp
   }
   let obj = Array.isArray(data) ? [] : {}
   cache.set(data,obj)
   for (let key of Reflect.ownKeys(data)) {
     let v = data[key]
     if (Array.isArray(data) && key === 'length') continue;
     obj[key] = deepClone(v,cache)
   }
   return obj
}