【Js】对象深拷贝

function deepCopy(data, hash = new WeakMap()) {
      if(typeof data !== 'object' || data === null){
            throw new TypeError('传入参数不是对象')
        }
      // 判断传入的待拷贝对象的引用是否存在于hash中
      if(hash.has(data)) {
            return hash.get(data)
        }
      let newData = {};
      const dataKeys = Object.keys(data);
      dataKeys.forEach(value => {
         const currentDataValue = data[value];
         // 基本数据类型的值和函数直接赋值拷贝 
         if (typeof currentDataValue !== "object" || currentDataValue === null) {
              newData[value] = currentDataValue;
          } else if (Array.isArray(currentDataValue)) {
             // 实现数组的深拷贝
            newData[value] = [...currentDataValue];
          } else if (currentDataValue instanceof Set) {
             // 实现set数据的深拷贝
             newData[value] = new Set([...currentDataValue]);
          } else if (currentDataValue instanceof Map) {
             // 实现map数据的深拷贝
             newData[value] = new Map([...currentDataValue]);
          } else { 
             // 将这个待拷贝对象的引用存于hash中
             hash.set(data,data)
             // 普通对象则递归赋值
             newData[value] = deepCopy(currentDataValue, hash);
          } 
       }); 
      return newData;
  }