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Building a dropdown menu using Alpine.js

Last modified June 28th 2021 | #alpine | GitHub Source Code [GitHub]

Alpine is a small JavaScript framework for composing behavior directly in HTML markup. In this tutorial I’ll show you how the framework can be used to build a dropdown menu component. If you’ve never worked with Alpine before this will serve as a simple introduction to the framework.

For the purposes of this tutorial you can load the framework via CDN:

<script src="https://unpkg.com/alpinejs@3.x.x/dist/cdn.min.js"></script>
Code language: HTML, XML (xml)

With Alpine loaded create a wrapper <div> with the following attributes:

<div x-data="{ open: false }" x-on:click.outside="open = false"> // ... </div>
Code language: HTML, XML (xml)

x-data defines a chunk of HTML as an Alpine component and provides data for that component to reference. x-on:click.outside set’s the open data to false which will hide the dropdown when anywhere outside the component is clicked.

Next inside the wrapper <div> add a button that’ll trigger the dropdown’s visibility:

<button x-on:click="open = !open"> My Account </button>
Code language: HTML, XML (xml)

Another x-on:click this time we’re only tracking clicks directly on the button itself.

Now for the dropdown menu which is an unordered list with a x-show attribute:

<ul x-show="open"> <li><a href="#">Edit Profile</a></li> <li><a href="#">Settings</a></li> <li><a href="#">Log Out</a></li> </ul>
Code language: HTML, XML (xml)

When open equals true the x-show attribute will change the visibility of the <ul> element. At this point in the tutorial we have a basic functioning dropdown, let’s add a couple of finishing touches to improve the look and feel. First let’s add an icon that’ll represent the state of the dropdown menu:

<button x-on:click="open = !open"> My Account <span :class="{'rotated': open}">&raquo;</span> </button>
Code language: HTML, XML (xml)

If you view the source code after the button has been clicked you’ll see the rotated class has been applied to the <span> element:

Alpine.js code with class added

We can now apply some CSS to rotate the icon indicating the menu is open:

.rotated { transform: rotate(90deg); display: inline-block; }
Code language: CSS (css)

Finally we’ll add a transition so the opening and closing of the dropdown appears smoother:

<ul x-show="open" x-transition.opacity> ... </ul>
Code language: HTML, XML (xml)

That’s all for this tutorial. As you’ve just seen by adding some simple Alpine attributes to HTML markup it relatively easy to create a functioning dropdown menu. With what you learnt in this tutorial you could also start building other UI elements with show/hide functionality and Alpine.js.

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