Reverse a String in JavaScript

Difficulty Level : Basic
Last Updated : 16 Apr, 2019

Given an input string and the task is to reverse the input string.

Examples:

Input: str = "Geeks for Geeks"
Output:  "skeeG rof skeeG"

Input: str = "Hello"
Output: "olleH"

There are many methods to reverse a string in JavaScript some of them are discussed below:

Method 1:

Check the input string that if given string is empty or just have one character or it is not of string type then it return “Not Valid string”.
If the above condition false create an array where we can store the result. Here revArray[] is the new array.
Loop through the array from the end to the beginning and push each and every item in the array revArray[].
Use join() prebuilt function in JavaScript to join the elements of an array into a string.

Example:

<script>
function ReverseString(str) {
  
    // Check input
    if(!str || str.length < 2 || 
            typeof str!== 'string') {
        return 'Not valid'; 
    }
      
    // Take empty array revArray
    const revArray = [];
    const length = str.length - 1;
      
    // Looping from the end
    for(let i = length; i >= 0; i--) {
        revArray.push(str[i]);
    }
      
    // Joining the array elements
    return revArray.join('');
}
  
document.write(ReverseString("Geeks for Geeks"))
</script>

Output:

skeeG rof skeeG

Method 2:

Use split() inbuilt function in JavaScript to split string into array of characters i.e. [ ‘G’, ‘e’, ‘e’, ‘k’, ‘s’, ‘ ‘, ‘f’, ‘o’, ‘r’, ‘ ‘, ‘G’, ‘e’, ‘e’, ‘k’, ‘s’ ]
Use reverse() function in JavaScript to reversal the array of characters i.e. [ ‘s’, ‘k’, ‘e’, ‘e’, ‘G’, ‘ ‘, ‘r’, ‘o’, ‘f’, ‘ ‘, ‘s’, ‘k’, ‘e’, ‘e’, ‘G’ ]
Use join() function in JavaScript to join the elements of an array into a string.

Example:

<script>
  
// Function to reverse string
function ReverseString(str) {
   return str.split('').reverse().join('')
}
  
// Function call 
document.write(ReverseString("Geeks for Geeks"))
</script>

Output:

skeeG rof skeeG

Method 3:

Use spread operator instead of split() function to convert string into array of characters i.e. [ ‘G’, ‘e’, ‘e’, ‘k’, ‘s’, ‘ ‘, ‘f’, ‘o’, ‘r’, ‘ ‘, ‘G’, ‘e’, ‘e’, ‘k’, ‘s’ ]. Learn more about the spread operator here Spread Operator
Use reverse() function in JavaScript to reversal the array of characters i.e. [ ‘s’, ‘k’, ‘e’, ‘e’, ‘G’, ‘ ‘, ‘r’, ‘o’, ‘f’, ‘ ‘, ‘s’, ‘k’, ‘e’, ‘e’, ‘G’ ]
Use join() function in JavaScript to join the elements of an array into a string.

Example:

<script>
const ReverseString = str => [...str].reverse().join('');
  
document.write(ReverseString("Geeks for Geeks"))
</script>

Output:

skeeG rof skeeG

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