The 0 is necessary if no args are passed. This is never the case for this challenge, but if we're going to overengineer it to work with args[n>0] we might as well cover the extra case.

The , 0 starting value isn't required in this reduce Starting with the first value in the array is fine, here.

Thanks, @colbydauph !

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions

"An arrow function expression has a shorter syntax than a function expression and does not have its own this, arguments, super, or new.target..."

Is there a way to do this with regex?

Oh, wow. I didn't even notice that bit. That makes complete sense.

Yeah. When this solution was written (2015-04-24T17:59:22.000Z, judging by the MongoDB ID in the link), there was only Node 0.10 or something like that on Codewars.

It's best to use "const" instead of "var" when defining a function.

Oh wow, this is fantastic!

great use of regex!

I like your use of ".filter"!

Sorry abou tnot cleaning this up before submitting it!

Every element of the sequence satisfies a condition that certain power (e.i. ANY) of the sum of its digits is equal to the number itself. Your calculations are correct but the test cases are fine as well ;)