JavaScript Reverse String

Introduction

A reverse string is a string whose characters are in reverse order.

Reversing a string in JavaScript involves creating a new string with the original string’s characters in the opposite order. This can be achieved by converting the string to an array, reversing it, and then joining it back into a string.

For example:

Original String: Hello

Reversed String: olleH

What is JavaScript Reverse String?

JavaScript reverse string means converting a string into the opposite order of characters.

Example:

"JavaScript";

Reversed string:

"tpircSavaJ";

Method 1: Reverse String Using split(), reverse(), join()

This is the most popular method.

string.split("").reverse().join("")

Example:

let text = "John";
let result = text.split("").reverse().join("");
console.log(result);

Output:

Explanation:

1. split:

Converts a string into an array.

"John".split("")

Output:

2. reverse()

Reverses array elements.

Output:

3. join(“”)

Converts the array back into a string.

Output:

Method 2: Reverse String Using a for Loop

Example:

let text = "JavaScript";

let reversed = "";

for(let i = text.length - 1; i >= 0; i--){
   reversed += text[i];
}

console.log(reversed);

Output:

Explanation:

Loop starts from the last character and adds characters one by one.

Method 3: Reverse String Using a while Loop

let str = "Coding";

let reversed = "";
let i = str.length - 1;

while(i >= 0){
   reversed += str[i];
   i--;
}

console.log(reversed);

Output:

Method 4: Reverse String Using Recursion

Recursion means a function calling itself.

Example:

function reverseString(str){

   if(str === "")
       return "";

   return reverseString(str.substr(1))
          + str.charAt(0);
}

console.log(reverseString("Hello"));

Output:

Method 5: Reverse String Using reduce()

Example:

let text = "Java";

let reversed =
text.split("")
.reduce((rev,char)=>char+rev,"");

console.log(reversed);

Output:

Method 6: Reverse String Using for…of Loop

Example:

let str = "World";

let reverse = "";

for(let char of str){
   reverse = char + reverse;
}

console.log(reverse);

Output:

Reverse Words Instead of Characters

Sometimes you need to reverse words.

Original:

I am John

Reversed:

John am I

Example:

let text = "I am John";
let result = text.split(" ").reverse().join(" ");
console.log(result);

Output:

Reverse Number Converted into String

When you have to reverse a number.

Example:

let number = 12345;
let result = number.toString().split("").reverse().join("");
console.log(result);

Output:

Common Mistakes While Reversing a String

You will see some common mistakes

Mistake 1: Forgetting to join()

Wrong:

name = "John";
let result = name.split("").reverse();
console.log(result);

Output:

Returns an array instead of a string.

Correct:

name = "John";
let result = name.split("").reverse().join();
console.log(result);

Output:

Mistake 2: Using reverse() Directly on String

Wrong:

name = "John";
let result = name.reverse();
console.log(result);

JavaScript Reverse String – Interview Questions

JavaScript Reverse String – Objective Questions (MCQs)

Conclusion

JavaScript reverse string is a common operation used in interviews, algorithms, and real-world applications. Since strings do not support the reverse() method directly, developers usually convert strings into arrays using split(), reverse them using reverse(), and then convert back using join().

You can also reverse strings using loops, recursion, and reduce() functions. Learning multiple approaches improves problem-solving skills and helps in coding interviews.