Also, where are the random tests?

No random tests?

Does not provide any failure messages.
Besides that, nice idea and nice kata.
Thank you

There is a little typo in the description: "jsFunction" [...] which should jst return the corresponding array property value"

Why is the solution area prefilled with
var websites = [];?
Would it not be better to start with sth like:

function stringArray(arrayStr, functionOrProperty, optionalArgs) {
  // Your code here
}