1function reverseString(s){
2    return s.split("").reverse().join("");
3}
4reverseString("Hello");//"olleH"

1"this is a test string".split("").reverse().join("");
2//"gnirts tset a si siht"
3//as a function
4function reverseString(string){
5return string.split("").reverse().join("");}
6reverseString("test string");
7//"gnirts tset"

1"this is a test string".split("").reverse().join("");
2//"gnirts tset a si siht"
3
4// Or
5const reverse = str => [...str].reverse().join('');
6
7// Or
8const reverse = str => str.split('').reduce((rev, char)=> `${char}${rev}`, '');
9
10// Or
11const reverse = str => (str === '') ? '' : `${reverse(str.substr(1))}${str.charAt(0)}`;
12
13// Example
14reverse('hello world');     // 'dlrow olleh'

1//with built-in method
2let string = "We are going to reverse a string with built-in method.";
3let reversed = string.split("").reverse().join("");
4console.log(reversed);
5
6//with the for loop
7let string = "We are going to reverse a string with the for loop.";
8function reverse (string){
9  let reversed = "";
10  for(let char of string){
11    reversed = char + reversed;
12  }
13  return reversed;
14}
15console.log(reverse(string));
16
17//with the spread operator
18let string = "We are going to reverse a string with the spread operator.";
19let reversed = [...string].reverse().join("");
20console.log(reversed);
21
22//with iteration
23let string = "We are going to reverse a string with iteration.";
24function reverse(string) {
25  for (var reversed = "", i = string.length - 1; i >= 0; i--) {
26    reversed += string[i];
27  }
28  return reversed;
29console.log(reverse(string));

1function reverse(str){  
2  let reversed = "";      
3   for (var i = str.length - 1; i >= 0; i--){         
4     reversed += str[i];  
5   }     
6  return reversed;
7}

1function reverseString(str) {
2  return str
3    .split("")
4    .reverse()
5    .join("");
6}
7