Склонение числительных в javascript

gistfile1.js

function declOfNum(number, titles) {  
    cases = [2, 0, 1, 1, 1, 2];  
    return titles[ (number%100>4 && number%100<20)? 2 : cases[(number%10<5)?number%10:5] ];  
}

use:
declOfNum(count, ['найдена', 'найдено', 'найдены']);

function declOfNum(count, one, two, few) {
    return [few, one, two, two, two, few][count % 100 > 10 && count % 100 < 20 ? 0 : Math.min(count % 10, 5)]
}

JSDoc + Using new ES features + can return number with declined string

/**
 * Declines depending on the number
 * @param {number} number
 * @param {string[]} titles Strings for decline
 * @param {boolean} [full=false] If true - returns number + string
 * @return {string}
 */
export function declOfNum (number, titles, full = false) {
  const cases = [2, 0, 1, 1, 1, 2]

  const result = titles[(number % 100 > 4 && number % 100 < 20) ? 2 : cases[(number % 10 < 5) ? number % 10 : 5]]
  return full ? `${number} ${result}` : result
}