I have
let f = x => x % 4 === 0 ? 0 : 4 - x % 4
But that's a piece of garbage function. Help.
x is never going to be negative.
Here's a sort of Table of Truth, or something.
x x % 4 4 - (x % 4) f(x)
0 0 4 0
1 1 3 3
2 2 2 2
3 3 1 1
4 0 4 0
5 1 3 3
6 2 2 2
7 3 1 1
8 0 4 0
9 1 3 3
I'm trying to find some correlations here, but it's late and I don't think my brain is working correctly. zzz
What I'm seeing in the f(x) column is a sort of reverse modulus, whereby the outputs cycle from 032103210... instead of 01230123...
I'm sensing some use of Math.max or Math.min in combination with Math.abs might help … There's probably an x * -1 in there somewhere too …
Can you help me write f such that it doesn't suck so badly ?
Something like this will definitely do:
(4 - (x % 4)) % 4
Here's some more truth:
x x % 4 4 - (x % 4) (4 - (x % 4)) % 4
0 0 4 0
1 1 3 3
2 2 2 2
3 3 1 1
4 0 4 0
5 1 3 3
6 2 2 2
7 3 1 1
8 0 4 0
9 1 3 3