Reverse a String with different methods.

reverseString.js

// Reverse a string with the Array.reverse() method, recursive method, the for loop method, or the ES6+ method.
const revString = 'olraC si eman ym iH'

/**
 * Reversing a string with a for loop
 * @param str | string
 * @returns | string
 */
function forLoopStringReversal(str) {
  let newStr = '';
  
  for (let i = 0; i < str.length; i++) {
    newStr = str[i] + newStr;
  }
  return newStr;
}

forLoopStringReversal(revString); // 'Hi my name is Carlo'

// time complexity: O(n)
// space complexity: O(1)

/**
 * Reversing a string with the Array.reverse() method
 * @param str | string
 * @returns | string
 */
function stringReversal(str) {
  return str.split('').reverse().join('');
}

stringReversal(revString); // 'Hi my name is Carlo'

// time complexity: O(n)
// space complexity: O(1)

/**
 * Reversing a string with recursion
 * @param str | string
 * @returns | string
 */
function recursiveStringReversal(str) {
  let newStr = '';
  
  if (!str.length) return '';

  newStr = recursiveStringReversal(str.slice(1)) + str[0]; 
  return newStr;
}

recursiveStringReversal(revString); // 'Hi my name is Carlo'

// time complexity: O(n)
// space complexity: O(1)

/**
 * Using ES6+ syntax
 * @param str | string
 * @returns | string
 */
const es6StringReversal = str => [...str].reverse().join('');

es6StringReversal(rev);

// time complexity: O(n)
// space completxity: O(1)

// See jsPerf for performance results: https://jsperf.com/stringreversal