深拷贝和浅拷贝实现方式

深拷贝
JSON方法实现
//_tmp和result是相互独立的，没有任何联系，有各自的存储空间。

let deepClone = function (obj) {
let _tmp = JSON.stringify(obj);//将对象转换为json字符串形式
let result = JSON.parse(_tmp);//将转换而来的字符串转换为原生js对象
return result;
};

let obj1 = {
weiqiujaun: {
age: 20,
class: 1502
},
liuxiaotian: {
age: 21,
class: 1501
}
};

let test = deepClone(obj1);
console.log(test);

 

2.用for…in实现遍历和复制

function deepClone(obj) {
let result = typeof obj.splice === "function" ? [] : {};
if (obj && typeof obj === 'object') {
for (let key in obj) {
if (obj[key] && typeof obj[key] === 'object') {
result[key] = deepClone(obj[key]);//如果对象的属性值为object的时候，递归调用deepClone,即在吧某个值对象复制一份到新的对象的对应值中。
} else {
result[key] = obj[key];//如果对象的属性值不为object的时候，直接复制参数对象的每一个键值到新的对象对应的键值对中。
}

}
return result;
}
return obj;
}

let testArray = ["a", "b", "c", "d"];
let testRes = deepClone(testArray);
console.log(testRes);
console.log(typeof testRes[1]);

let testObj = {
name: "weiqiujuan",
sex: "girl",
age: 22,
favorite: "play",
family: {brother: "son", mother: "haha", father: "heihei"}
};
let testRes2 = deepClone(testObj);
testRes2.family.brother = "weibo";
console.log(testRes2);

 

3.利用数组的Array.prototype.forEach进copy

let deepClone = function (obj) {
let copy = Object.create(Object.getPrototypeOf(obj));
let propNames = Object.getOwnPropertyNames(obj);
propNames.forEach(function (items) {
let item = Object.getOwnPropertyDescriptor(obj, items);
Object.defineProperty(copy, items, item);

});
return copy;
};

let testObj = {
name: "weiqiujuan",
sex: "girl",
age: 22,
favorite: "play",
family: {brother: "wei", mother: "haha", father: "heihei"}
}
let testRes2 = deepClone(testObj);
console.log(testRes2);

 

浅拷贝（使用object.assign方法）

let target=[];
let testArr=[2,3,5,8];
Object.assign(target,testArr);
console.log(target);
testArr.push(8);
console.log("我是原来的"+target+",我是现在的"+testArr);