递归实现深拷贝

    if (typeof obj !== 'object') return obj

    var newObj = (Object.prototype.toString.call(obj) === '[object Array]') ? [] : {}

    for (var key in obj) {

        if (obj.hasOwnProperty(key)) {

            newObj[key] = (typeof obj[key] !== 'object') ? obj[key]: deepCopy(obj[key])

        }
    }
    return newObj
}