Adding a New Line in JavaScript (Tutorial)

Still learning? These are the best ways to add a new line to your JavaScript code’s output.

Published Categorized as JavaScript, Web & Code

Suppose you’re working on a function for your web app, and that function outputs a long line of text. To make the output easier for your users to read, you’ll probably want to add a line break here and there.

What’s the best way to do this?

JavaScript, like most other programming languages, has support for the so-called “end of line” or “newline” character. This character is written as \n and inserts a line break on the screen.

However, there is a case where you might want to do something else, especially if you’re building a frontend, and we’ll get to it in a moment.

To add a new line to a string in JavaScript, add the \n character where you want the line to break to show. If you’re writing HTML elements directly into the DOM, consider inserting a <br> element instead.

Read on for code examples and details as to why.

Adding a New Line to a String

To see how the newline character works in practice, let’s output the following haiku, a Japanese form of short poetry, by Katsushika Hokusai:

I will write, erase, rewrite

Erase again, and then

A poppy blooms.

“A Poppy Blooms” by Katsushika Hokusai

Who knew coding had so much in common with poetry, right?

To output this haiku, we need to save it in a variable, making sure we preserve the line breaks as they are:

let poem = "I will write, erase, rewrite\nErase again, and then\nA poppy blooms";

If you opened up your browser’s developer tools right now (as I encourage you to do) and copy/paste this into the console, this is what you’d get:

Nine times out of ten, this should do the trick. But, as I mentioned, there’s one case where you may need to do something different, and that case is when you’re writing HTML to the DOM.

Adding a Line Break to the HTML Output

If you’re using JavaScript to write HTML elements directly into the DOM, whether with document.write(), innerHTML(), or insertAdjacentHTML(), you will want to add your line breaks with a <br> element so that they render in the browser.

This is a common scenario for code that powers headless CMS implementations and for CRM implementations that insert opt-in forms on the frontend. (Though the use cases for it are limited only by the imagination and ingenuity of the JavaScript developer.)

For example, let’s assume there’s a placeholder for a poem in a <div> element with an ID of “poem:”

<div id="poem"></div>

Let’s also assume you want to write the haiku poem above directly into that placeholder using JavaScript.

let poem = "I will write, erase, rewrite<br>Erase again, and then<br>A poppy blooms";
let placeholder = document.getElementById("demo");
placeholder.innerHTML = poem;

Notice that, instead of the \n character, we’re inserting the <br> element. This is because, in this example, it’s the browser’s rendering engine that builds the output on the screen, not the JavaScript interpreter—and the browser’s rendering engine expects to see HTML markup.

Were you to run this code, it would populate the placeholder <div> with the poem, along with the necessary <br> line breaks:

<div id="poem">I will write, erase, rewrite<br>Erase again, and then<br>A poppy blooms</div>

Job done 🙂

In Conclusion

To add a new line to a string in JavaScript, use the \n character. However, if you’re writing HTML directly into the DOM, you will want to use the <br> element.

As with any JavaScript development problem, there’s more than one solution and various ways to approach their implementations. If you can think of any edge cases or limitations of the above, or you came across them as you tried them, leave a comment below.

Image courtesy of spaxiax /Depositphotos

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