Walker_Category_Checklist::start_el( string $output, WP_Term $data_object, int $depth = 0, array $args = array(), int $current_object_id = 0 )

Compatibility

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

Parameters

$outputstring

Used to append additional content (passed by reference).

$data_objectWP_Term

The current term object.

$depthintoptional

Depth of the term in reference to parents. Default 0.Default: 0

$argsarrayoptional

An array of arguments. See wp_terms_checklist().Default: array()

$current_object_idintoptional

ID of the current term. Default 0.Default: 0

Performance profile

How much work a call to Walker_Category_Checklist::start_el() 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

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

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

Instructions

63–119

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 158.

Plugin surface

1 hook

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

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach option, cache, serialize, query 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 · 6 distinct outcomes

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

Hooks and filters fired · 2

2 hooks fire while Walker_Category_Checklist::start_el() runs, in this order:

1. 1
   apply_filters( the_category )filterline 108 (+35 into the body)

   Filters the category or list of categories.

2. 2
   apply_filters( the_category )filterline 120 (+47 into the body)

   Filters the category or list of categories.

Uses · 6

• esc_html()Escaping for HTML blocks.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• wp_unique_prefixed_id()Generates an incremental ID that is independent per each different prefix.
• esc_attr()Escaping for HTML attributes.
• checked()Outputs the HTML checked attribute.
• disabled()Outputs the HTML disabled attribute.

Source code

View on Trac ↗View on GitHub ↗

73	public function start_el( &$output, $data_object, $depth = 0, $args = array(), $current_object_id = 0 ) {74		// Restores the more descriptive, specific name for use within this method.75		$category = $data_object;76 77		if ( empty( $args['taxonomy'] ) ) {78			$taxonomy = 'category';79		} else {80			$taxonomy = $args['taxonomy'];81		}82 83		if ( 'category' === $taxonomy ) {84			$name = 'post_category';85		} else {86			$name = 'tax_input[' . $taxonomy . ']';87		}88 89		$args['popular_cats'] = ! empty( $args['popular_cats'] ) ? array_map( 'intval', $args['popular_cats'] ) : array();90 91		$class = in_array( $category->term_id, $args['popular_cats'], true ) ? ' class="popular-category"' : '';92 93		$args['selected_cats'] = ! empty( $args['selected_cats'] ) ? array_map( 'intval', $args['selected_cats'] ) : array();94 95		if ( ! empty( $args['list_only'] ) ) {96			$aria_checked = 'false';97			$inner_class  = 'category';98 99			if ( in_array( $category->term_id, $args['selected_cats'], true ) ) {100				$inner_class .= ' selected';101				$aria_checked = 'true';102			}103 104			$output .= "\n" . '<li' . $class . '>' .105				'<div class="' . $inner_class . '" data-term-id=' . $category->term_id .106				' tabindex="0" role="checkbox" aria-checked="' . $aria_checked . '">' .107				/** This filter is documented in wp-includes/category-template.php */108				esc_html( apply_filters( 'the_category', $category->name, '', '' ) ) . '</div>';109		} else {110			$is_selected         = in_array( $category->term_id, $args['selected_cats'], true );111			$is_disabled         = ! empty( $args['disabled'] );112			$li_element_id       = wp_unique_prefixed_id( "in-{$taxonomy}-{$category->term_id}-" );113			$checkbox_element_id = wp_unique_prefixed_id( "in-{$taxonomy}-{$category->term_id}-" );114 115			$output .= "\n<li id='" . esc_attr( $li_element_id ) . "'$class>" .116				'<label class="selectit"><input value="' . $category->term_id . '" type="checkbox" name="' . $name . '[]" id="' . esc_attr( $checkbox_element_id ) . '"' .117				checked( $is_selected, true, false ) .118				disabled( $is_disabled, true, false ) . ' /> ' .119				/** This filter is documented in wp-includes/category-template.php */120				esc_html( apply_filters( 'the_category', $category->name, '', '' ) ) . '</label>';121		}122	}

Changelog

Introduced in 2.5.1. 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 6.9.7 tag, from src/wp-admin/includes/class-walker-category-checklist.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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