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Solving `Cannot read property 'cloneNode' of undefined` in Alpine.js

August 11, 2021  ‐ 2 min read

If you are developing with Alpine.js you may encounter the following error at some point:

Alpine Expression Error: Cannot read property 'cloneNode' of undefined

Most likely you are using the x-if directive on an HTML element other than <template>. In Alpine.js, the x-if directive should only be applied on <template> elements and not on the element you wish to hide or display with conditional rendering.

So let's consider the following element for example.

<h1 x-if="page === ''">Home</h1>

In order to get the above to work properly we need to wrap the h1 in a template tag. As is shown in the following example:

<template x-if="page === ''">

The <template> tag is a special HTML5 tag that is not visually rendered on a webpage directly. Instead it is meant to be instantiated with JavaScript once a page is loaded. You can think of it as an elements that just holds content, which you can render dynamically and reuse multiple times if you need to. A side note here is that Internet Explorer does not support the usage of the <template> tag.

Alternatively you can possibly use x-show instead of x-if if it better suits your use-case. The x-show directive uses CSS to hide elements and therefore doesn't require the use of the <template> tag. Alpine does so by setting the display property to "none".

Further Readings: