SOURCE

//浅拷贝
function shallowClone(target) {
    if(typeof target === 'object' && target !== null){
        if(Array.isArray(target)){
            return [...target]
        }else{
            return {...target}
        }
    }else{
        return target;
    }
}

// const obj = {a:1,b:{m:2}}
// const cloneObj = shallowClone(obj);
// obj.b.m = 5;
// console.log('clone--',cloneObj)

// console.log('obj--',obj)

function deepClone1(target) {
    return JSON.parse(JSON.stringify(target));
}
// const obj = {
//     a: 1,
//     b: { m: 2 },
//     c: [1, 2, 3],
//     // 不能克隆方法
//     d() {},
// };
// 会造成循环引用
// obj.c.push(obj.b);
// obj.b.j = obj.c;
// const cloneObj = deepClone1(obj);
// obj.c.push(666);
// console.log(obj);
// console.log(cloneObj);


function deepClone2(target,map = new Map()){
    if(typeof target === 'object' && target !== null){
        const cache = map.get(target);
        if(cache){
            return cache;
        }
        const result = Array.isArray(target)?[]:{}
        map.set(target,result)
        for(const key in target){
            if(target.hasOwnProperty(key)){
                result[key] = deepClone2(target[key],map)
            }
        }
        return result;
    }else{
        return target;
    }
}

const obj = {a:1,b:{m:2}}
const cloneObj = deepClone2(obj);
obj.b.m = 5;
console.log('obj--',obj)
console.log('clone--',cloneObj)