Adding an algorithm AlphaNumericPalindrome from freecodecamp

String/AlphaNumericPalindrome.js

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+/**
+ * alphaNumericPlaindrome should return true if the string has alphanumeric characters that are palindrome irrespective of special characters and the letter case
+ * @param {string} str the string to check
+ * @returns `Boolean`
+ */
+
+/*****************************************************************************
+ * What is a palindrome? https://en.wikipedia.org/wiki/Palindrome
+ *
+ * The function alphaNumericPlaindrome() recieves a sting with varying formats
+ * like "racecar", "RaceCar", and "race CAR"
+ * The string can also have special characters
+ * like "2A3*3a2", "2A3 3a2", and "2_A3*3#A2"
+ *
+ * But the catch is, we have to check only if the alphanumeric characters
+ * are palindrome i.e remove spaces, symbols, punctuations etc
+ * and the case of the characters doesn't matter
+ *
+ * This is one of the questions/projects that we have to solve for the
+ * JavaScript Algorithms and Data Structures course on https://www.freecodecamp.org
+ *
+ * Author -- Syed Fasiuddin
+ * https://github.com/SyedFasiuddin
+ *
+ ****************************************************************************/
+
+const alphaNumericPlaindrome = (str) => {
+  // removing all the special characters and turning everything to lowercase
+  const newStr = str.replace(/[^a-zA-Z0-9]*/g, '').toLowerCase()
+  // the newStr variable is a string and only has alphanumeric characters all in lowercase
+
+  // making an array of individual characters as it's elements
+  const arr = newStr.split('')
+
+  // setting a variable to see if change occurs to it
+  let palin = 0
+
+  // making a copy of arr with spread operator
+  const arrRev = [...arr]
+  // you can use arrRev.reverse() to reverse the array
+  // or else you can use the below method
+
+  // iterate through the arr and check the condition of palindrome
+  for (let i = 0; i < arr.length; i++) {
+    if (arr[i] !== arrRev[arr.length - 1 - i]) {
+      // if the string is not palindrome then we change palin varaible to 1
+      palin = 1
+    }
+  }
+
+  // if the string is palindrome then palin variable is never changed
+  if (palin == 0) return true
+  else return false
+}
+
+// test cases
+// alphaNumericPlaindrome("eye");
+// alphaNumericPlaindrome("0_0 (: /-\ :) 0-0")
+// alphaNumericPlaindrome("five|\_/|four")
+// alphaNumericPlaindrome("A man, a plan, a canal. Panama")
+
+export { alphaNumericPlaindrome }

String/test/AlphaNumericPalindrome.test.js

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+import { alphaNumericPlaindrome } from '../AlphanumericPalindrome'
+
+test('should return true if the given string has alphanumeric characters that are palindrom irrespective of case and symbols', () => {
+  expect(alphaNumericPlaindrome('eye')).toBe(true)
+})
+
+test('should return true if the given string has alphanumeric characters that are palindrom irrespective of case and symbols', () => {
+  expect(alphaNumericPlaindrome('0_0 (: /-\ :) 0-0')).toBe(true)
+})
+
+test('should return true if the given string has alphanumeric characters that are palindrom irrespective of case and symbols', () => {
+  expect(alphaNumericPlaindrome('five|\_/|four')).toBe(false)
+})
+
+test('should return true if the given string has alphanumeric characters that are palindrom irrespective of case and symbols', () => {
+  expect(alphaNumericPlaindrome('A man, a plan, a canal. Panama')).toBe(true)
+})
+
+test('should return true if the given string has alphanumeric characters that are palindrom irrespective of case and symbols', () => {
+  expect(alphaNumericPlaindrome('1 eye for of 1 eye.')).toBe(false)
+})