• 深拷贝：修改复制对象，原始对象不会变化
• 浅拷贝：修改复制对象，原始对象也变化

方式：

• 遍历赋值
• Object.create()
• JSON.parse()和JSON.stringify()

操作的对象

var obj = {a: "Hello",b: {a: "world",b: 111,},c: [11, "Jack", "Tom"],
};

1、浅拷贝

1-1、遍历赋值

// 浅拷贝
function simpleCopy(o) {var o_ = {};for (let i in o) {o_[i] = o[i];}return o_;
}var newObj = simpleCopy(obj);
newObj.b.a = "WORLD";
console.log(obj);console.log(newObj);/**
obj 和 newObj都变了：
b: { "a": "WORLD", "b": 111}}
*/

1-2、Object.create()

var newObj = Object.create(obj);
newObj.b.a = "WORLD";console.log(obj);
// b: {a: "WORLD", b: 111}
console.log(newObj);
// __proto__:
// b: {a: "WORLD", b: 111}

2、深拷贝

2-1、遍历赋值

function deepCopy(object, deepObject=null) {let deepObj = deepObject || {};for (let i in object) {if (typeof object[i] === "object") {// 引用类型 [] {} nullif(object[i] === null){deepObj[i] = object[i];} else{deepObj[i] = object[i].constructor === Array ? []: {}// deepObj[i] = object[i].constructor === Array ? []: Object.create(null);deepCopy(object[i], deepObj[i])}} else{// 简单数据类型deepObj[i] = object[i];}}return deepObj;
}var newObj = deepCopy(obj);
newObj.b.a = "WORLD";console.log(obj);
// b: {a: "world", b: 111}
console.log(newObj);
// b: {a: "WORLD", b: 111}

2-2 JSON

function deepCopy(o) {return JSON.parse(JSON.stringify(o));
}var newObj = deepCopy(obj);
newObj.b.a = "WORLD";console.log(obj);
// b: {a: "world", b: 111}
console.log(newObj);
// b: {a: "WORLD", b: 111}