rustamgarifulin

const numfix = (n, t) => t[
       (n %= 100, 20 > n && n > 4) ? 2
         :[2,0,1,1,1,2][ (n %= 10, n < 5) ? n : 5]
   ]
;

const a = ['день','дня','дней'];
console.log(numfix(1, a)); // день
console.log(numfix(2, a)); // дня
console.log(numfix(5, a)); // дней

rustamgarifulin

Keybase proof

I hereby claim:

• I am rustamgarifulin on github.
• I am rustamgarifulin (https://keybase.io/rustamgarifulin) on keybase.
• I have a public key whose fingerprint is FC00 009D 4404 80D1 7734 46DB 06DC 6F3C B0B8 855F

To claim this, I am signing this object: