Ranks can't be changed.

That isn't a kata issue, though it could be a CW issue at the time.

Not an issue, your code's problem is a question.

JS functions can only accept a certain number of arguments before getting into problems ;-)

if the number of the array's values is even return truthy values otherwise return falsy ones.

[ true, {} ] has 2 elements, and you have to return the truthy values in that array, so you should return the same array given true and {} are both truthy.

It says: when there are no corresponding values (false in this case) return empty array.

No, the corresponding values are truthy in that case.

if the number of the array's values is even return truthy values...
Number of values = 2
Truthy values: true, {}
Expected: [true, {}]

What's wrong with that?