手写递归方法实现深拷贝

function deepClone(obj){
  if(typeof obj !=='object'|| obj == null)  {
    return obj;
  }
  let cloneObj;

  if(obj instanceof Array){
    return cloneObj = [];
  }else{
    return cloneObj={};
  }

  for(let key in obj){
    cloneObj(obj[key])=deepClone(obj[key]);
  }
  return cloneObj;
  
}