@expyth it's not the fastest but it's easy to read. Take a look at @rowcased's comment above where he provides benchmarks.

I don't get how this solution is the fastest.
It has 2 for loops.
Can someone explain?

I'm the same way. Says I can't pass 3 tests but can't fiture out why I can't pass them

Figured it out. For those passing most tests but having trouble with a few here's a hint: Check that what's happening when you compare the "enteredCode" and "currentCode" params are what you're expecting to happen.

Cannot pass 3 tests. Not sure why, seems like there is some kind of error with the tests?

✔ Test Passed: Value == true
Log
CurrentDate
September 5, 2014
2014-10-05T00:00:00.000Z
1412467200000

ExpirationDate
September 25, 2014
2014-10-25T00:00:00.000Z
1414195200000

✘ Expected: false, instead got: true
Log
CurrentDate
September 5, 2014
2014-10-05T00:00:00.000Z
1412467200000

ExpirationDate
September 25, 2014
2014-10-25T00:00:00.000Z
1414195200000

✘ Expected: false, instead got: true
Log
CurrentDate
September 5, 2014
2014-10-05T00:00:00.000Z
1412467200000

ExpirationDate
September 25, 2014
2014-10-25T00:00:00.000Z
1414195200000

✘ Expected: false, instead got: true
Log
CurrentDate
March 5, 1998
1998-04-05T00:00:00.000Z
891734400000

ExpirationDate
March 25, 1998
1998-04-25T00:00:00.000Z
893462400000

Thanks, of course now my code works fine :)

Nope.

You stop before empty spaces if you approach them vertically (like in your case) and you skip them if you approach them horizontally.

No idea, you're the sensei. But if I come up with anything I'll drop you a line. ;)

Thank you.
Part 3... any idea would be welcome, but what's left?