Examples of Recursion

recursion.js

var factorial = function(num) {
  if (num < 2) {
    return 1;
  }

  return num * factorial(num - 1);
};

var isPalindrome = function (expression) {
  // A single character string eg 'a' and the empty string "" are palindromes
  // since they read the same forwards and backwards

  if (expression.length <= 1) {
    return true;
  }

  if (expression.charAt(0) !== expression.charAt(expression.length - 1)) {
    return false;
  }

  var chars = expression.split("");
  chars.shift();
  chars.pop();

  var smallerExpression = chars.join("");
  return isPalindrome(smallerExpression);
};