Some of Js Challenge Questions

let numbersArr = [4, 6, 7, 9, 12];

function findSecondBiggestNumber(numbers) {
  numbers.sort((a, b) => a - b);
  return numbers[numbers.length - 2];
}

// console.log(findSecondBiggestNumber(numbersArr));

let strForReverse = "Erhan";

function reverseGivenString(str) {
  return str.toLowerCase().split("").reverse().join("");
}

// console.log(reverseGivenString(strForReverse));

let strForPalindrome = "Xox";

function isPalindrome(str) {
  if (str.toLowerCase() === reverseGivenString(str)) return true;
  else return false;
}

// console.log(isPalindrome(strForPalindrome));

let inputForPerfectNr = 6;

function isPerfectNumber(number) {
  let positiveDivisors = [],
    sumOfDivisors = 0;

  let numbersArr = new Array(number - 1)
    .fill(0)
    .map((element, index) => index + 1);

  numbersArr.forEach((nr) => {
    if (number % nr === 0) positiveDivisors.push(nr);
  });

  positiveDivisors.forEach((divisor) => (sumOfDivisors += divisor));

  if (sumOfDivisors === number) return true;
  else return false;
}

console.log(isPerfectNumber(inputForPerfectNr));