How to do a reverse-word function in Javascript

Question

I'm trying to do a reverse-word script in javascript. I have written this function, but it does not work and I can't understand why. What is wrong? Is there any other way to do it?

function inverser(x)
{
    var newString ="";
    var index=(x.length - 1);
    var y=0;
    
    for (var i=index ; i>=0 ; i--)
    {
        x[i] = newString [y++];
    }
    
    return (newString );
}

console.log(inverser("test"));

Possible duplicate of [How do you reverse a string in place in JavaScript?](http://stackoverflow.com/questions/958908/how-do-you-reverse-a-string-in-place-in-javascript) — Alex, May 07 '17 at 16:02
Your assignment is in reverse. And strings are immutable, you cannot assign to their indices at all. Use an array instead, or build the string through concatenation. — Bergi, May 07 '17 at 16:02
"but it does not work" isn't a very helpful description of your problem. What *is* the output for a given input? And what have you done to debug it? — Carcigenicate, May 07 '17 at 16:02
It should be: `newString [y++] = x[i];` not `x[i] = newString [y++];` — Karim Harazin, May 07 '17 at 16:02

score 1 · Accepted Answer · answered May 07 '17 at 16:07

1

You need to add to concatenate newString instead of trying to assign an index to it. The logic of your function should be

newString[y++] += x[i];

Link to code

answered May 07 '17 at 16:07

Garrett Kadillak

1,026
9
18

Abishek V Ashok · Answer 2 · 2017-05-08T04:33:33.053

0

Use reverse():

function inverser(x)
{   
    return x.split("").reverse().join("");
}

It's simple if you don't need build in function, please comment, i will update my answer :)

Update

The assignment statements are wrong in your code, it should have been:

newString += x[i];

edited May 08 '17 at 04:33

answered May 07 '17 at 16:07

Abishek V Ashok

513
3
17

Thanks. Yes, I know that function, but I want to understand why my code does not work – PNB May 07 '17 at 16:10
Your assignment statement is wrong @PNB, I have updated my answer. – Abishek V Ashok May 08 '17 at 04:29

score 0 · Answer 3 · answered May 07 '17 at 16:22

when you use newString[y++], newString is still empty string and doesn't have cell 1 or 2 or 3 .... and can't assign string to this cell.

simply if you remove y variable and make some move on line 9 can get answer.

here the code worked for me:

function inverser(x) {
  var newString = "";
  var index = (x.length - 1);

  for (var i = index; i >= 0; i--)
  {
    newString += x[i];
  }

  return (newString);
}

score 0 · Answer 4 · answered Dec 22 '22 at 07:37

"use strict";
function wordReverse() {
  const str1 = "God is Good";
  const str2 = str1.split(" ");
  //console.log(str2);
  const reverseWord = [];
  const len = str2.length;
  //console.log(len);
  for (let i = len - 1; i >= 0; i--) {
    reverseWord.push(str2[i]);
  }
  return reverseWord;
}
console.log(wordReverse().join(" "));

score 0 · Answer 5 · answered Dec 22 '22 at 07:49

0

const word = "reverse";
const reverseString = (str) => str.split("").reverse().join("");
reverseString(word);

answered Dec 22 '22 at 07:49

Eran Peled

767
6
6

score 0 · Answer 6 · answered Dec 22 '22 at 08:05

function reverseWord(str) {
    const splittedString = str.split(" ");
    const wordreverse = [];
    const len = splittedString.length;

    for (let i = len - 1; i >= 0; i--) {
            wordreverse.push(splittedString[i]);
    }
    return wordreverse.join(" ");
}

score 0 · Answer 7 · answered Dec 22 '22 at 08:07

function reverseWord(str) {
    const splittedString = str.split(" ");
    const wordreverse = [];
    const len = splittedString.length;

    for (let i = len - 1; i >= 0; i--) {
            wordreverse.push(splittedString[i]);
    }
    return wordreverse.join(" ");
}
console.log(reverseWord("hello world"))

How to do a reverse-word function in Javascript

7 Answers7