As part of clarifying what is part of the open source offering and what is examples or private code, we should signal these differences using package names/namespaces.

Suggested solution:

• Let all public, published packages retain their @backstage namespace.
• Change all private packages in the open source project (plugins/home-page, plugins/welcome) to be under an @internal names

https://github.com/trekhleb/javascript-algorithms/blob/master/src/algorithms/sets/cartesian-product/cartesianProduct.js#L8

I think it makes more sense to return an empty array

// invalid input return null or throw an error
if (!setA || !setB) {
    return null;
}
if (!setA.length || !setB.length) {
    return []; 
}
// or do nothing since the for loop will not trigger anyway

感谢您对DeepLearn-500-questions的支持，让我能拿到google的offer，随机抽取数位给过我赞的人发送红包，请扫码进入群聊找我领(QQ邮箱请点击显示图片)
发件人：tzlgkw@163.com

虽然可能不是作者发的，但这样实在过分。提醒大家里面的二维码是红包码，这个作用都知道，但我挂出来就是为了防止更多人被欺骗。

Updated

OK，可以基本确定不是仓库 Owner 所为。而且有人用脚本监控了 Star 的用户的邮箱，并使用了随机的 163 邮箱。追查可能不太现实，大家不要相信即可。

In the Readme file you talk about a future website. Why not create a GitHub Page? Is very easy to configure and the content of the web is what you have in your readme file. Perfect, no?