get_post_class() │ WP 2.7.0

Retrieves the classes for the post div as an array.

The class names are many. If the post is a sticky, then the 'sticky' class name. The class 'hentry' is always added to each post. If the post has a post thumbnail, 'has-post-thumbnail' is added as a class. For each taxonomy that the post belongs to, a class will be added of the format '{$taxonomy}-{$slug}' - eg 'category-foo' or 'my_custom_taxonomy-bar'.

The 'post_tag' taxonomy is a special case; the class has the 'tag-' prefix instead of 'post_tag-'. All class names are passed through the filter, post_class, with the list of class names, followed by $class parameter value, with the post ID as the last parameter.

Used By: post_class()

1 time — 0.00616 sec (very slow) | 50000 times — 10.72 sec (slow) | PHP 7.0.2, WP 4.4.1

Hooks from the function

post_class

Return

String[]. Array of class names.

Usage

get_post_class( $class, $post_id );

$class(string|string[]): Space-separated string or array of class names to add to the class list.
Default: ''
$post_id(int|WP_Post): Post ID or post object.
Default: null

Examples

#1 Output demonstration

$classes = get_post_class();
print_r( $classes );

/*
Array
(
	[0] => post-219
	[1] => post
	[2] => type-post
	[3] => status-publish
	[4] => format-standard
	[5] => has-post-thumbnail
	[6] => hentry
	[7] => category-blog
	[8] => tag-novosti
)
*/

#2 Let's output all classes as a string

This code can be used as a replacement for post_class():

<div class="<?= join( ' ', get_post_class() ) ?>">

#3 Adding our own classes

// as string
$classes = get_post_class( 'foo bar' );

// or as array
$classes = get_post_class( [ 'foo', 'bar' ] );

/* 
Both examples will add to the resulting array

Array
(
	[0] => foo
	[1] => bar
	[2] => post-19
)
*/

#4 Delete unnecessary class

Suppose we need to get rid of the class hentry, then use this filter before calling get_post_class() or post_class():

add_filter( 'post_class', 'remove_hentry' );

function remove_hentry( $classes ) {

	$unset = array( 'hentry' ); // you can add more

	return array_diff( $classes, $unset );
}

Changelog

Since 2.7.0	Introduced.
Since 4.2.0	Custom taxonomy class names were added.

Code of `get_post_class() get post class` ^{WP 6.0.1}

wp-includes/post-template.php

function get_post_class( $class = '', $post_id = null ) {
	$post = get_post( $post_id );

	$classes = array();

	if ( $class ) {
		if ( ! is_array( $class ) ) {
			$class = preg_split( '#\s+#', $class );
		}
		$classes = array_map( 'esc_attr', $class );
	} else {
		// Ensure that we always coerce class to being an array.
		$class = array();
	}

	if ( ! $post ) {
		return $classes;
	}

	$classes[] = 'post-' . $post->ID;
	if ( ! is_admin() ) {
		$classes[] = $post->post_type;
	}
	$classes[] = 'type-' . $post->post_type;
	$classes[] = 'status-' . $post->post_status;

	// Post Format.
	if ( post_type_supports( $post->post_type, 'post-formats' ) ) {
		$post_format = get_post_format( $post->ID );

		if ( $post_format && ! is_wp_error( $post_format ) ) {
			$classes[] = 'format-' . sanitize_html_class( $post_format );
		} else {
			$classes[] = 'format-standard';
		}
	}

	$post_password_required = post_password_required( $post->ID );

	// Post requires password.
	if ( $post_password_required ) {
		$classes[] = 'post-password-required';
	} elseif ( ! empty( $post->post_password ) ) {
		$classes[] = 'post-password-protected';
	}

	// Post thumbnails.
	if ( current_theme_supports( 'post-thumbnails' ) && has_post_thumbnail( $post->ID ) && ! is_attachment( $post ) && ! $post_password_required ) {
		$classes[] = 'has-post-thumbnail';
	}

	// Sticky for Sticky Posts.
	if ( is_sticky( $post->ID ) ) {
		if ( is_home() && ! is_paged() ) {
			$classes[] = 'sticky';
		} elseif ( is_admin() ) {
			$classes[] = 'status-sticky';
		}
	}

	// hentry for hAtom compliance.
	$classes[] = 'hentry';

	// All public taxonomies.
	$taxonomies = get_taxonomies( array( 'public' => true ) );
	foreach ( (array) $taxonomies as $taxonomy ) {
		if ( is_object_in_taxonomy( $post->post_type, $taxonomy ) ) {
			foreach ( (array) get_the_terms( $post->ID, $taxonomy ) as $term ) {
				if ( empty( $term->slug ) ) {
					continue;
				}

				$term_class = sanitize_html_class( $term->slug, $term->term_id );
				if ( is_numeric( $term_class ) || ! trim( $term_class, '-' ) ) {
					$term_class = $term->term_id;
				}

				// 'post_tag' uses the 'tag' prefix for backward compatibility.
				if ( 'post_tag' === $taxonomy ) {
					$classes[] = 'tag-' . $term_class;
				} else {
					$classes[] = sanitize_html_class( $taxonomy . '-' . $term_class, $taxonomy . '-' . $term->term_id );
				}
			}
		}
	}

	$classes = array_map( 'esc_attr', $classes );

	/**
	 * Filters the list of CSS class names for the current post.
	 *
	 * @since 2.7.0
	 *
	 * @param string[] $classes An array of post class names.
	 * @param string[] $class   An array of additional class names added to the post.
	 * @param int      $post_id The post ID.
	 */
	$classes = apply_filters( 'post_class', $classes, $class, $post->ID );

	return array_unique( $classes );
}