get_comment_class( string|string[] $css_class = '', int|WP_Comment $comment_id = null, int|WP_Post $post = null ): string[]

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$css_classstring|string[]optional

One or more classes to add to the class list.
Default empty.Default: ''

$comment_idint|WP_Commentoptional

Comment ID or WP_Comment object. Default current comment.Default: null

$postint|WP_Postoptional

Post ID or WP_Post object. Default current post.Default: null

Return value

string[]

An array of classes.

Performance profile

How much work a call to get_comment_class() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via get_post().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

13–113

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 120.

Plugin surface

1 hook

Third-party callbacks on 'comment_class' run inside this call, and their cost is not bounded by anything here.

Called by

2

2 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• querycontent queryget_post()called directly
• hookthird-party callbacksapply_filters()called directly
• regexregular expression over the whole inputpreg_split()called directly

Further down the call graph this can also reach option, cache, serialize and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 13 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost get_comment_class() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 1

One hook fires while get_comment_class() runs, in this order:

1. 1
   apply_filters( comment_class )filterline 599 (+79 into the body)

   Filters the returned CSS classes for the current comment.

Uses · 5

• get_comment()Retrieves comment data given a comment ID or comment object.
• get_userdata()Retrieves user info by user ID.
• sanitize_html_class()Sanitizes an HTML classname to ensure it only contains valid characters.
• get_post()Retrieves post data given a post ID or post object.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 2

• WP_Comments_List_Table::single_row()
• comment_class()Generates semantic classes for each comment element.

Source code

View on Trac ↗View on GitHub ↗

520function get_comment_class( $css_class = '', $comment_id = null, $post = null ) {521	global $comment_alt, $comment_depth, $comment_thread_alt;522 523	$classes = array();524 525	$comment = get_comment( $comment_id );526	if ( ! $comment ) {527		return $classes;528	}529 530	// Get the comment type (comment, trackback).531	$classes[] = ( empty( $comment->comment_type ) ) ? 'comment' : $comment->comment_type;532 533	// Add classes for comment authors that are registered users.534	$user = $comment->user_id ? get_userdata( $comment->user_id ) : false;535	if ( $user ) {536		$classes[] = 'byuser';537		$classes[] = 'comment-author-' . sanitize_html_class( $user->user_nicename, $comment->user_id );538		// For comment authors who are the author of the post.539		$_post = get_post( $post );540		if ( $_post ) {541			if ( $comment->user_id === $_post->post_author ) {542				$classes[] = 'bypostauthor';543			}544		}545	}546 547	if ( empty( $comment_alt ) ) {548		$comment_alt = 0;549	}550	if ( empty( $comment_depth ) ) {551		$comment_depth = 1;552	}553	if ( empty( $comment_thread_alt ) ) {554		$comment_thread_alt = 0;555	}556 557	if ( $comment_alt % 2 ) {558		$classes[] = 'odd';559		$classes[] = 'alt';560	} else {561		$classes[] = 'even';562	}563 564	++$comment_alt;565 566	// Alt for top-level comments.567	if ( 1 === $comment_depth ) {568		if ( $comment_thread_alt % 2 ) {569			$classes[] = 'thread-odd';570			$classes[] = 'thread-alt';571		} else {572			$classes[] = 'thread-even';573		}574		++$comment_thread_alt;575	}576 577	$classes[] = "depth-$comment_depth";578 579	if ( ! empty( $css_class ) ) {580		if ( ! is_array( $css_class ) ) {581			$css_class = preg_split( '#\s+#', $css_class );582		}583		$classes = array_merge( $classes, $css_class );584	}585 586	$classes = array_map( 'esc_attr', $classes );587 588	/**589	 * Filters the returned CSS classes for the current comment.590	 *591	 * @since 2.7.0592	 *593	 * @param string[]    $classes    An array of comment classes.594	 * @param string[]    $css_class  An array of additional classes added to the list.595	 * @param string      $comment_id The comment ID as a numeric string.596	 * @param WP_Comment  $comment    The comment object.597	 * @param int|WP_Post $post       The post ID or WP_Post object.598	 */599	return apply_filters( 'comment_class', $classes, $css_class, $comment->comment_ID, $comment, $post );

Changelog

Introduced in 2.7.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.8.8 tag, from src/wp-includes/comment-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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