We can.

Correct syntax would be this.valueOf = () => value.

Yes, thank you very much!

why can't we just do:

var Foo = function(value){
this.val=value
return this.valueOf(this.val)
}

or something like that?

Can anyone explain? Thanks :-)

There's no need for "innerLen". Description states: "All 2D arrays passed into your function will be square (NxN)". Therefore "innerLen" always equals to "len".

Our algorithms are the same, but a few neat hacks I added FYI:

1. the "len" and "innerLen" variables cache the lengths of the inner and outer arrays, so they only be computed once
2. the number 1 is truthy, so your if statement need not require the equals condition