BugWP logo BugWP
Back to Community
Home / Community / Core → Developing with wordpress

Why Your Block's Frontend Styles and Scripts Aren't Loading (And How to Fix It)

14 threads Sep 16, 2025 Core → Developing with wordpress

Content

A common hurdle developers face when building custom Gutenberg blocks is ensuring that the necessary CSS and JavaScript files load correctly on the frontend of the site. It's a frequent point of confusion, as styles and scripts might appear perfectly in the block editor but fail to show up for site visitors. This guide will explain the core concepts and provide the most common solutions to get your assets loading properly.

The Core Concept: Block.json Properties

The modern way to register block assets is through the block.json file. Understanding the purpose of each property is the first step to troubleshooting. The key properties for frontend assets are:

  • style: Provides a stylesheet for both the editor and the frontend.
  • viewScript: Provides a script that is only enqueued on the frontend.
  • script: Provides a script that is enqueued on both the editor and the frontend.

A common mistake is using editorStyle when you intend to style the frontend, as editorStyle is, by definition, for the editor only. For frontend styles, you should use the style property.

Common Problem 1: Missing the 'style' Property

As seen in Thread 1, a block might have editorStyle defined, which loads CSS in the editor, but lack a style property, which is required to load the same CSS on the frontend.

Solution: Ensure your block.json includes the correct property. For a stylesheet that must appear everywhere, use style.

{
  "style": "file:./style-index.css"
}

Common Problem 2: viewScript Module Dependencies

Thread 2 highlights an issue where a script registered with viewScript (which uses modern ES modules) tries to import third-party libraries. The WordPress script module system may not handle these external dependencies as expected, leading to the script failing on the frontend.

Solution: The most reliable method is to enqueue the third-party library dependency separately using traditional PHP methods, like wp_enqueue_script(), and then use your view.js to initialize your block using that globally available library.

Common Problem 3: Scripts Loading Too Early

Thread 11 describes a scenario where a script from block.json loads but throws an "is not defined" error because it depends on a library that hasn't loaded yet or because the script itself executes before the DOM is fully ready.

Solution: For scripts that manipulate the DOM, always wrap your code in an event listener to ensure it runs after the document is ready. For dependencies, enqueue libraries with proper dependency handling in PHP.

// In your view.js file
document.addEventListener('DOMContentLoaded', () => {
    // Your initialization code here
});

When to Use PHP Enqueuing

As referenced in Threads 2, 4, and 7, the block.json method is not always sufficient. For complex scenarios, conditional loading, or integrating with external CDNs, falling back to PHP is the recommended approach.

You can use the wp_enqueue_style() and wp_enqueue_script() functions within the render_block filter to conditionally load assets only when your specific block is present on the page. This is a powerful method for optimizing performance.

Summary and Best Practices

  • Double-check your block.json: Confirm you are using style for frontend CSS, not editorStyle.
  • For complex scripts: Use viewScript for your block's initialization code, but enqueue large, third-party libraries from PHP.
  • Wrap DOM-dependent code: Always ensure your frontend scripts wait for the DOMContentLoaded event.
  • Know when to use PHP: For maximum control over dependencies and conditional loading, use traditional WordPress enqueuing methods alongside block.json.

By understanding the roles of the different block.json properties and knowing when to supplement them with PHP, you can reliably ensure your block's assets load correctly on the frontend.

Related Support Threads Support