Could you please share the link where I can read more about this solution)

I like this one. Very functional and easy to read.

Obviously this is best practice

You have a missing semicolon

@alexschrod awesome answer, thank you for explaining so succinctly

dang and I thought mine is simple enough

Problem with this solution is that it is O(n) and solution can be O(1)

Same decision :)

I know this is old, but can someone explain where the s comes into play?
I know the left side s is the parameter but the right side s is what is returned, but how does that return if the vale is true if there is only the parameter.

Not quite right. A recursive solution like this is exponential (at least 1.6^n). O(n) is actually very good.