HTML comment block vs. php conditional content

[eningan]

Hello,

I am currently trying to update an old theme to the 5.9 version (FSE).

I'm stuck on a concept, the transition from PHP pages to HTML pages.

Concretely, I am trying to replace the name of my category with an icon.
In PHP I could include conditional code that checked the category of the post and I could change the content of the link (in the taxonomy-category div) to an image.

Can you explain to me the method to reproduce the following code with the new HTML blocks?

In my single.ph file :

<div class="post-categories">
	<?php
	// Display categories icons
	$icoCategories = array("castors", "loups", "scouts", "unite", "pionniers", "photos", "intro-posts");
	
	foreach((get_the_category()) as $category) {
		$catName = $category->slug;

		if(in_array($catName, $icoCategories)) {
			$category_link = get_category_link( $category->cat_ID );
			echo '<a href="'.esc_url( $category_link ).'" target="_self" class="ico-'.strtolower($category->slug).'"> </a>';
		}
	}
	?>
</div>

In the single.html file :

<!-- wp:post-terms {"term":"category"} /-->

It's obviously possible to do with javascript, even with a hook in the functions.php file but I would have liked to keep it in the single.html file.

What is the best method, a filter, a pattern ... ?
In general I would like to know how to modify the result generated by the HTML comment blocks (can we make personalized arguments?).

As I'm a bit lost, I hope my question is clear.

Thank you in advance

[t-hamano]

Hi,

The Post Terms block (Categories, Tag) calls get_the_term_list internally.

In other words, it passes through the following filter hooks:

• get_the_terms
• term_links-{$taxonomy}
• pre_term_link
• tag_link
• category_link
• term_link

There does not appear to be a way to add your own class name to the a element in these hooks, but you may be able to accomplish something similar with the following:

add_filter('get_the_terms', function( $terms, $post_id, $taxonomy ) {
	$new_terms = array();

	foreach ( $terms as $term ) {
		if ( 'some-rule' === $term->slug ) {
			$term->name = '<span class="some-icon-classes">' . $term->name . '</span>';
		}
		$new_terms[] = $term;
	}

	return $new_terms;
}, 10, 3 );