深拷贝

 var cat = {
            name :'mini',
            eat: function(){
                console.log('fish');
            },
            cute: {
                s:'miaomiao'
            },
            un: undefined
       }
function deepClone(obj) {
            let valClone = Array.isArray(obj) ? [] : {};
            for(let key in obj) {
                if(obj.hasOwnProperty(key)) {
                    if(typeof obj[key] === 'object' && obj[key]) {
                        valClone[key] = deepClone(obj[key])
                    } else {
                        valClone[key] = obj[key]
                    }
                }
            }
            return valClone
     }