- The Go one (averaging) is non-idiomatic, and has a nasty bug in it: https://news.ycombinator.com/item?id=27698287

- The JavaScript one (memoization) is a bad implementation, it doesn't handle some argument types you'd expect it to handle: https://news.ycombinator.com/item?id=27698125

You can tell a lot about what to expect, if there are so many bugs in the very examples used to market this product.