Why this code is not working as expected? I want to reverse a string but it is outputting the same string

Question

When I write same logic in C programming it reverse the string but in Javascript it is not working, Can somebody help to figure out why? Thanks in advance.

function reverse(str) {
  let res=str;
  for(let i = 0; i < str.length/2; i++) {
     let temp = res[i];
    res[i] = res[res.length-i-1];
    res[res.length-i-1] = temp;
  }
  return res;
}


console.log(reverse("anil"))

Answer 1

Strings in JavaScript are immutable.

You can read a character from a position with foo[index] but you can't write to it.

Convert the string to an array of single-character strings with split. Then convert it back to a string (with join) at the end.

function reverse(str) {
  let res = str.split("");
  for (let i = 0; i < str.length / 2; i++) {
    let temp = res[i];
    res[i] = res[res.length - i - 1];
    res[res.length - i - 1] = temp;
  }
  return res.join("");
}


console.log(reverse("anil"))

That said. Arrays have a reverse method, so you don't need to reinvent the wheel.

function reverse(str) {
  let res = str.split("");
  res.reverse();
  return res.join("");
}


console.log(reverse("anil"))