Reverse a String in JavaScript or Node.js

There are situations when you want to reverse a given string value. This tutorial shows you how to reverse a string from a given value.

Node.js Series Overview

Reverse a String in JavaScript

JavaScript doesn’t have a native Str#reverse method. Yet, you can use the existing methods to build your own method to reverse a string.

Creating the reverse string requires you to split an existing string into an array of its characters. JavaScript’s array class comes with a reverse method allowing you to reverse the order of the characters. Then you must join the items in the array back to a string value:

/**
 * Returns the reverse of the given string `value`.
 * 
 * @param {String} value
 * 
 * @returns {String}
 */
function reverse(value) {  
  return Array.from(
    String(value || '')
  ).reverse().join('')
}

Then use the created reverse function like this:

reverse('Super')  
// 'repuS'

reverse('cool 🥳')  
// '🥳 looc'

reverse(null)  
// ''

reverse()  
// ''

Notice: we’re using Array.from(<string-value>) to split a given string into a list of characters. The reason is: Array.from(<string-value>) supports UTF-16 characters, like emojis, which then creates a character for each emoji.

Be careful when using „string.split('')“

Be careful when using string.split('') to split the given string into its characters. The String#split method doesn’t handle UTF-16 characters like emojis. The list of characters would then lose the emojis as individual characters. That’s the reason we recommend using Array.from() to create an array of characters from a given string.

Use the @supercharge/strings Package

I’m the maintainer of the @supercharge/strings package providing convenient string utilities. It provides a useful Str#reverse() method returning the reversed string value. It also provides solid emoji and UTF-16 character handling:

const Str = require('@supercharge/strings')

Str('Super').reverse().get  
// 'repuS'

Str('cool 🥳').reverse().get  
// '🥳 looc'

Str(null).reverse().get()  
// ''

Str().reverse().get()  
// ''

That’s it!


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