深拷贝

深拷贝是拷贝多层，每一层数据都会拷贝

1、JSON.parse(JSON.stringify())

JSON.stringify()进行深拷贝有弊端： 忽略value为function, undefind, symbol, 并且在序列化BigInt时会抛出语法错误：TypeError: Do not know how to serialize a BigInt

let data = {
    a: undefined,
    b: 2,
    c: { x: 111 }
};
let newData = JSON.parse(JSON.stringify(data));

2、自定义递归深拷贝

const deepCopy = (obj) => {
    if (!obj || typeof obj !== "object") return obj;
    let result = {};
    if (Reflect.toString.call(obj).indexOf("Array") > 0) {
        result = [];
    }
    Object.keys(obj).forEach((key) => {
        result[key] = deepCopy(obj[key]);
    });
    return result;
};

浅拷贝

浅拷贝是拷贝单层，更深层次的对象还是指向引用地址

1、Object.assign() || {...obj}

let aa = {
    a: undefined,
    func: function () {
        console.log(1);
    },
    b: 2,
    c: { x: "xxx", xx: undefined },
    d: null,
    e: BigInt(100),
    f: Symbol("s")
};
let bb = Object.assign({}, aa); //  或者 let bb = {...aa}
aa.c.x = 111;
console.log(bb);

4、Object.create() && Object.getOwnPropertyDescriptors()

let aa = {
    a: undefined,
    func: function () {
        console.log(1);
    },
    b: 2,
    c: { x: "xxx", xx: undefined }
};
let bb = Object.create(null, Object.getOwnPropertyDescriptors(aa));
aa.c.x = 111;
console.log(bb);

参考

JS实现深拷贝和浅拷贝的方式详解