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

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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。