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In this article, we will show you how to implement dynamic imports with Alpine.js, load them with a delay using the Intersection Observer API and thus improve the accessibility of your own site and content.
SetupDownload Astro Boilerplate
If our boilerplate isn’t right for you, that’s no problem. The steps for implementing dynamic imports work in any project with Alpine.js.
In the following steps, we will install the dependencies required for the subsequent implementation of dynamic imports.
npm install alpinejs @alpinejs/intersect
To demonstrate the dynamic import, we use Chart.js,
a simple library for the visualization of charts via the
npm install chart.js
After successfully installing all dependencies, we can start our development
environment – in the example of our Astro Boilerplate with
npm run dev:
npm run dev
Preparation of the HTML
To visualize Chart.js in the frontend and to be able to understand our
implementation later, we place a
<canvas> element with the following
Implementation of Chart.js
In our demonstration, we follow the example of the Getting Started
guide of Chart.js and implement a simple bar chart within our
chart(), we register the asynchronous method
which we have already referenced in our
once() we import
registerables asynchronously from the
chart.js package and register all required modules of Chart.js
Finally, the bar chart is implemented with a rudimentary data set. Further information on the functionality of Chart.js can be found in the corresponding documentation.
Configuration of Alpine.js
For reasons of clarity, we have moved the
chart() method to a separate file,
which we must now reference when initializing Alpine.
However, before we can reference our method in Alpine, we have to initialize
intersect plugin. With
Alpine.plugin(intersect) the imported plugin can
be initialized and made available via Alpine.
Finally, we add the directive
Alpine.data("chart", chart) to the
We first presented our pattern for development with Alpine.js in our article Temporary and persistent state management with Alpine.js.
Once we have made all the adjustments, we can verify our desired results with the network analysis of the browser dev tools.
In our scenario, the Chart.js library is only loaded via
once() when the
<canvas> element enters the viewport for the first time.
Assuming that we need the entire library for our project, we have reduced the initial transfer by ~70 kB (gzip) with this implementation.
The implementation of Chart.js is just one of many examples in which dynamic imports help to reduce the initial transfer of a website and make content accessible more quickly.
This function is not limited to libraries. It can also be used for more complex components or larger data sets with little additional effort.
In a further step, the loading of this content can be bridged with a loading animation that is controlled via a data object in Alpine.
In this article, we demonstrated how to use Alpine.js and the Intersection Observer API to delay the loading of libraries like Chart.js until they are needed, improving load time and user experience.