How to reverse a string in JavaScript [Step-by-step]

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Updated onOctober 4, 2023

updated onOctober 4, 2023

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Key notes

A palindrome is a word or list of characters that read the same when reversed. A good example of this is the word ‘RADAR’.

The easiest way to check for a palindrome inJavaScriptis to create a copy of the original string, reverse it, and then compare it. If you want to build an algorithm that does this effectively, you’ll need to learn how to reverse a string inJavaScript. In this guide, you’ll learn how.

How do I reverse a string with JavaScript?

1. Convert it into an array and reverse it

The best way to implement the above steps is through a function. Here’s a quick source code example that you can copy, test, and modify:

In the above example, we create a function that reverses a hard-coded string and then sets a document element to it. The function is then called from a button labeled ‘Reverse’.

There are numerous ways you can shorten and modify this code. For instance, instead of assigning the joined string to thestrvariable, you can reassign it to to theresvariableand then point the demo HTML document element to it i.e.

res = res.join("");document.getElementById(“demo”).innerHTML = res;

Alternatively, you can condense all three steps into a single line:

var res = str.split("").reverse().join("");

Either way, the results should be the same:

Want to learn JavaScript even faster? Learn why you should download JavaScript Code by reading this article!

2. Reverse the string in JavaScript using a for loop

Once again, you should apply the above operation in a function within scripting tags. Whether you want to include theJavaScriptas an external file or embedded code is up to you. Here’s how the above solution looks in action:

The above code works by looping through your original string in reverse and clones it character by character. If you’re not interested in explicitly casting your string into an array, then you may find this solution more suited to your goals.

3. Reverse the string in JavaScript using recursion

You should call this method from another function that’s responsible for displaying the results. The complete code should look something like this:

Recursion works a lot like a for loop, but you’re trickingJavaScript‘s logic to work for you. Instead of appending characters to the end of the string, it attaches it to the front with each loop. Nevertheless, the results are much the same.

The above examples can be tested by using Windows Notepad and a web browser. However, we suggest using across-platform code editoror an integrated development environment to save yourself some time.

How to reverse a string in aJavascriptis a common interview question. Therefore, understanding it may be imperative to your success as a software developer.

Nonetheless, let us know which method worked best for you in the comments below. As always, thank you for reading.

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How to reverse a string in JavaScript [Step-by-step]#

How do I reverse a string with JavaScript?#

1. Convert it into an array and reverse it#

2. Reverse the string in JavaScript using a for loop#

3. Reverse the string in JavaScript using recursion#

How to reverse a string in JavaScript [Step-by-step]

How do I reverse a string with JavaScript?

1. Convert it into an array and reverse it

2. Reverse the string in JavaScript using a for loop

3. Reverse the string in JavaScript using recursion