如何实现JavaScript的深拷贝

var newobj = Object.assign({},obj);

function deepclone(obj) {
    let newobj = Array.isArray(obj) ? [] : {}; //在这里判断传入的类型然后初始化一个空的对象或数组
    for(let key in obj){
        let type = Object.prototype.toString.call(obj[key]);//判断对象属性的类型，如果为引用类型递归处理
        if( type === '[object Array]' || type === '[object Object]'){
            newobj[key] = deepclone(obj[key]);
        }
        else{
            newobj[key] = obj[key];
        }
    }
    return newobj;
}

var test = {
    score: [1,[3,4,5],3],
    name: 'petter',
    skill: {
        run: function () {
            console.log('I can run fast');
        } 
    }
} 

var mytest = deepclone(test);

mytest.name = 'jenny';

console.log('Myname is ' + test.name);

mytest.score[1].push(4);

console.log(mytest.score);

console.log(test.score);

mytest.skill.run = function () {
    console.log('I can\'t run fast');
}

test.skill.run();

mytest.skill.run();

{ score: [ 1, [ 3, 4, 5 ], 3 ],
  name: 'petter',
  skill: { run: [Function: run] } }
Myname is petter
[ 1, [ 3, 4, 5, 4 ], 3 ]
[ 1, [ 3, 4, 5 ], 3 ]
I can run fast
I can't run fast

var newobj = JSON.parse(JSON.stringify(obj));