[DrJokepu]

Basically the important bit to remember when using dynamic languages in production is that you have to be extremely serious about writing (good) tests. It’s easy to get lazy when using a statically typed language as the compiler will do much of the work for you (especially if you take full advantage of the type system’s features). You can’t get away with that when writing e.g. JavaScript.

[pjmlp]

That is exactly the main problem.

Enterprise developers don't write tests if their managers don't force them to, gets specially hairy when you have multiple consulting companies across multiple sites.

So you get JavaScript/Ruby/Python code with zero tests.

No sane people tries to refactor such code.