It would help to clarify which characters split up words -- do we only need to worry about spaces? Or should we also consider commas, periods, etc.

Also, the parameter order in your description is reversed from the parameter order in the tests.

This could use test cases. You have them in the description already. Otherwise, it was a fun kata.

The description says that myTasks takes an array, but it actually doesn't -- we're expected to take an arbitrary number of string arguments. This is a little confusing.

Also, it's a little confusing to have the boilerplate code start with a fake array inside the function and then a line at the end that executes the function.

It would be nice to have some examples, test cases, and discussion of how to handle edge cases.

"Jon has a string but its where the spaces (' ') should be there are commas (,)."

This is phrased confusingly.

The kata says this: "(Use integer division to divide the numbers, (if you actually use the division method))". But the tests expect you to use regular floating point division, not integer division.

Some tests fail on Run Tests due to floating point division errors (8.9999... vs 9), even though the kata says not to worry about this. When I actually submit to the server, though, my solution passes. This seems a little inconsistent.

One small suggestoin: The return value of the stubbed-out function should be bool instead of Boolean.

Seems to be a duplicate of the Valid Parentheses kata:
http://www.codewars.com/kata/valid-parentheses

Minor suggestion--
Because the examples in the problem description seem to output sentences, this could confuse someone into thinking that the output ought to be a string instead of a number. It might be helpful to make it clearer in these examples that the expected output is a number, and the sentences are just fluff.

In JS, specifying that the return value if no character is found should be undefined is a little odd. Why not make it null?

Trivial, but the title of the kata should be capitalized.

The text of the kata says this: "Find the first character that repeats in a String and return that character." It goes on to clarify that "this is not the same as finding the character that repeats first." The difference between "the first character that repeats" and "the character that repeats first" is extremely subtle, so the clarification (with the "tweet" example) is helpful--perhaps that could be made more prominent?