深拷贝
function deepClone(param) {
if(typeof param =='object' || param !==null){
return param;
}
let result;
if(param instanceof Array){
return []
}else {
return {}
}
for(let key in param){
if(param.hasOwnProperty(key)){
result[key] = deepClone(param[key])
}
}
return result;
}