Well the issue mentioned is that map calls the callback function with up to three arguments[1].

A type check could prevent this because it would require map to take a reference to a function with three parameters, or the compiler would complain inside the map implementation.

Similarly, passing it a function with only one parameter would be a type violation and the compiler would complain.

Now in a language with type checking, you could still potentially run afoul.

Say the map function was overloaded with one variant for one-parameter callbacks, one variant for two-parameter callbacks etc. Then the compiler might figure out it could use the second overload if the "toReadableNumber" function got changed to take the extra "base" parameter.

So again you end up with the numbers getting converted with a variable base.

Though, IMHO, having such an overloaded map function is inviting trouble and is a very poor design.

[1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...