Enhancing the WordPress Button Block

Recently, I worked on a feature involving the core/button block, which had been modified through custom scripts to display additional markup.

However, due to markup inconsistencies, achieving a unified design and interaction between the block editor and the frontend became a labor-intensive task. The solution required excessive CSS to ensure the block looked and functioned as intended. This led me to address the underlying issue — ensuring markup consistency between the editor and the frontend.

Why Consistency Matters

A key aspect of developing custom WordPress blocks is maintaining consistent markup between the block editor (Gutenberg) and the frontend. If the HTML structure differs, it can lead to:

• Styling inconsistencies (e.g., misaligned text, padding issues).
• Broken interactions, where styles apply only in one context.
• Long-term maintenance challenges, making updates and refinements harder.

Gutenberg provides a live preview of blocks within the editor. However, if the block’s structure changes between the editor and frontend, users may experience unexpected results after publishing.

Example Issue: Custom Button with an Icon

Consider a scenario where a custom button block includes an icon:

• If the icon is rendered as a pseudo-element in the editor but wrapped inside a <div> on the frontend, styles like display: flex may not behave as expected.
• If a wrapper <div> exists in the editor but not on the frontend, alignment, spacing, and interaction inconsistencies may arise.

To prevent these issues, the editor and frontend must generate identical or at least structurally similar HTML.

Some developers may hesitate to use filters due to potential core WordPress updates requiring adjustments, but I believe taking this approach is worthwhile.

Using Filters to Ensure Consistency

blocks.registerBlockType

This filter extends an existing block (e.g., core/button) by adding new attributes that both the block editor and frontend recognize.

Example Use: Adding an iconType attribute to store the selected icon and an iconSide attribute to control its position.

editor.BlockEdit

This filter modifies how a block appears inside Gutenberg, ensuring the block preview accurately matches the frontend.

Example Use: Injecting the selected SVG icon directly inside the button within the editor, so it renders exactly as it would on the frontend.
Bonus: Using useBlockProps() ensures that core WordPress behaviors, such as alignment settings, remain intact.

render_block

A PHP hook used to modify block output, guaranteeing consistency between the editor and frontend.

Example Use: Dynamically inserting the icon into the button before the text while preserving the block structure. This prevents styling inconsistencies and ensures the frontend markup matches the editor.

As a result, the CSS required to unify the aspect of the button with icon in the block editor and on the front end is simply this:

.wp-block-button.with-icon {
	& .wp-block-button__link {
		align-items: center;
		display: flex;
		gap: 1rem;

		& svg {
			fill: currentColor;
			margin: -0.25rem;
		}
	}

	&.with-icon-right {
		& .wp-block-button__link {
			flex-direction: row-reverse;
		}
	}

	& .button-icon {
		display: contents;
	}
}

Extend the Button Block: Demo

When adding new features, it’s beneficial to group controls together in the interface and provide a simple toggle to enable or disable the feature with one click.

Enhancements in my example:

• The toggle resets all icon-related attributes registered with the filters.
• Users can switch the icon position (left/right of the text) using native icons, making the change intuitive with a single click.

See the button in action:

Conclusion

When developing Gutenberg blocks, maintaining consistent markup between the editor and frontend is crucial for predictable styling and a smooth editing experience. By leveraging the right WordPress filters—blocks.registerBlockType, editor.BlockEdit, and render_block — we can ensure that the block behaves the same across both environments.