I think replace is better anyways. Don't need to worry about getting null returned, then have to check for it. null.length doesn't brake your code, because you where not turned a string or array.

a is the initial value while be is current value e.g 39 => 1 * 3 * 9

my solution is short

nice @teranetmk

using match didn't come to my mind. i had to use the linear equation

first

first try!

it means if no lost number return 0

Awww that Number to return 0 on a falsy value! Excellent idea.

easier

nice

easy

your solution is quadratic

Is this quadratic?

first try!!