前端数据拷贝（浅拷贝、深拷贝）

浅拷贝

1 直接赋值

2 扩展运算符（...)

3 abject.assign()

Object.assign({}, obj);

4 slice和concat

slice 截取数组

concat 拼接数组

深拷贝

1 JSON.parse(JSON.stringify(待拷贝对象))

2 使用第三方库 Lodash

const _ = require('lodash');

let obj = {
    name: 'demo',
    age: 26
}

let obj2 = _.cloneDeep(obj);
obj2.name = "demo_new";

console.log(obj); // {name: "demo", age: 26}
console.log(obj2); // {name: "demo_new", age: 26}

3 手写一个深拷贝

function deepClone (obj) {
    if (typeof obj !== 'object' || obj == null) {
        return obj;
    }
    
    let deepCloneObj = Array.isArray(obj) ? [] : {}
    
    for (let key in obj) {
        if (obj.hasOwnProperty(key)) {
            deepCloneObj[key] = deepClone(obj[key]);
        }
    }
    
    return deepCloneObj;
}