reverse array and string in javascript code example

Example 1: javascript string reverse

"this is a test string".split("").reverse().join("");
//"gnirts tset a si siht"

// Or
const reverse = str => [...str].reverse().join('');

// Or
const reverse = str => str.split('').reduce((rev, char)=> `${char}${rev}`, '');

// Or
const reverse = str => (str === '') ? '' : `${reverse(str.substr(1))}${str.charAt(0)}`;

// Example
reverse('hello world');     // 'dlrow olleh'

Example 2: reverse a word javascript

function reverseWords(str) {
  const allWords = str.split(" ")
  return allWords.map(item => item.split("").reverse().join("")).join(" ")
}