merge: alphaNumericPlaindrome optamization (#857)

String/AlphaNumericPalindrome.js

@@ -1,12 +1,10 @@
-/**
- * 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
- *
+ * @function alphaNumericPlaindrome
+ * @description 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}
+ * @see [Factorial](https://en.wikipedia.org/wiki/Palindrome)
+ * @example
  * The function alphaNumericPlaindrome() receives a string with varying formats
  * like "racecar", "RaceCar", and "race CAR"
  * The string can also have special characters
@@ -16,41 +14,19 @@
  * 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 variable to 1
-      palin = 1
+  for (let i = 0; i < newStr.length; i++) {
+    if (newStr[i] !== newStr[newStr.length - 1 - i]) {
+      return false
     }
   }
 
-  // if the string is palindrome then palin variable is never changed
-  if (palin === 0) return true
-  else return false
+  return true
 }
 
 export { alphaNumericPlaindrome }