浅拷贝和深拷贝

浅拷贝

function shallowCopy(target) {
    let newObj = {};
    for(let k in target) {
        if(target.hasOwnProperty(k)) {
            newObj[k] = target[k];
        }
    }
    return newObj;
}

深拷贝

function type(target) {
    return Object.prototype.toString.call(target).slice(8,-1);
}

function deepCopy(target) {
    if(type(target) == 'Function') {
        return new Function("return " + target.toString())();
    }else if(target === null || (typeof target !== 'object')) {
        return target;
    }else {
        let k, targetObj = (type(target)==='Array') ? [] : {}, value;
        for(k in target) {
            value = target[k];

            if(value === target){
                continue;
            }

            if (type(value)==='Array' || type(value)==='Object') {
                targetObj[k] = deepCopy(value);
            } else if (type(value)==='Function') {
                targetObj[k] = new Function("return " + value.toString())();
            } else {
                targetObj[k] = value;
            }

        }
    }

    return targetObj;
}