Categories Algorithms, JavascriptPosted on

JS Algorithm – Reverse Int

Chichén Itzá, Mérida, Mexico by https://unsplash.com/@mrvphotography

Given an integer, return an integer that is the reverse ordering of numbers.

Examples:

reverseInt(15) === 51
reverseInt(981) === 189
reverseInt(500) === 5
reverseInt(-15) === -51
reverseInt(-90) === -9

Solution:

function reverseInt(n) {
  // Converting the integer number to string.
  // then convert to an array and reverse that array
  // then with join we are back the array to string
  let reversedString = n.toString().split('').reverse().join('');

  // converting the string to integer
  // Math.sign => It returns 1 if the argument passed is a positive.
  // It returns -1 if the argument passed is a negative.
  return parseInt(reversedString) * Math.sign(n);
}

reverseInt(500);

Result:

By Cristina Rojas.