I'm shocked that over twice as many users solved this with the ternary than without.

what's the last 10 for ?

why u all reversing array?LOL

You're right, I've just refactored my solution. Thanks !

Why are you doing a terenary when it already returns a boolean?

Normally I'd say yes, giving parseInt a radix of 10 is best form. However, you really only have to worry about specifying a radix if the string could possibly have a leading "0x" or "0". E.g.

parseInt("0x10"); // -> 16
parseInt("010"); // -> 10 or 8, depending on implementation

Both of those are impossible in this case: we know that the string is a number in string form and the digits are sorted in descending order, so it can't possibly begin with "0x" or "0" (unless the number is 0, and then the radix is irrelevant).

I prefer +n anyway in most cases, because you can test that the result isn't NaN. parseInt and parseFloat provide no error handling whatsoever.