How to Reverse String in javascript

Question

I have string like below:

ABCDEFGH

And i want to reverse it like below:

GHEFCDAB

i have tried this:

  var str = "ABCDEFGH";
  var splitString = str.split("");
  var reverseArray = splitString.reverse();
  var joinArray = reverseArray.join("");

And return like below:

HGFEDCBA

I Know it wrong, and it just reverse it one way. how to reverse string in javascript with that condition? Many thank before.

So, you want to reverse every couple of letters, but leave the two letters in each group in the same order? — Oscar Paz, Jan 29 '20 at 11:17
Does this answer your question? [How do you reverse a string in place in JavaScript?](https://stackoverflow.com/questions/958908/how-do-you-reverse-a-string-in-place-in-javascript) — Ariando Miller, Jan 29 '20 at 11:18

score 4 · Accepted Answer · answered Jan 29 '20 at 11:22

You can do this, using regex : let splited = str.match(/.{1,2}/g).reverse().join('');

str.match(/.{1,2}/g) to transform ABCDEFGH to [AB, CD, EF, GH]
reverse() to transform [AB, CD, EF, GH] to [GH, EF, CD, AB]
join('') to transform [GH, EF, CD, AB] to GHEFCDAB

You can take a look here

Chaurasia · Answer 2 · 2020-01-29T12:52:29.267

Pairing string reverse

Using empty String

const str = 'ABCDEFGH'
var emptyStr = '';

for(let i = str.length; i>1; i--){
  emptyStr += str.slice(i-2,i)
  i--
}
console.log(emptyStr);

using empty Array

const str = 'ABCDEFGH'
const rev = str.split('');
const revStr = []

for(let i = str.length; i >=1; i--){
const strPair = rev.slice(i-2,i).join('');
  i--;
  revStr.push(strPair)
  }
console.log(revStr.join(''))

Output: GHEFCDAB

score 0 · Answer 3 · answered Dec 18 '20 at 15:42

class RevStr{
 
    constructor(input){
        this.str =input;
    }

    reverseStr() {
        let str = this.str.match(/.{1,2}/g)
        let end = str.length-1;
        let start = 0;

        while (start < end) {
            let temp = str[start];
            str[start] = str[end];
            str[end] = temp;
            start++;
            end--;
        }
        console.log(str.join(''));
    }

}
let s = new RevStr("abcdefgh");
s.reverseStr();

How to Reverse String in javascript

3 Answers3

Pairing string reverse