build_dropdown_script_block_core_categories( string $dropdown_id ): 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

$dropdown_idstring

ID of the dropdown field.

Return value

string

Returns the dropdown onChange redirection script.

Performance profile

How much work a call to build_dropdown_script_block_core_categories() 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

26

Executed per call on PHP 8.5. The body compiles to 26.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

1

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

What it touches

• hookthird-party callbacksapply_filters()one call below build_dropdown_script_block_core_categories()

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 · 1 distinct outcome

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

Uses · 3

• home_url()Retrieves the URL for the current site where the front end is accessible.
• wp_json_encode()Encodes a variable into JSON, with some confidence checks.
• wp_get_inline_script_tag()Constructs an inline script tag.

Used by · 1

• render_block_core_categories()Renders the `core/categories` block on server.

Source code

View on Trac ↗View on GitHub ↗

103function build_dropdown_script_block_core_categories( $dropdown_id ) {104	ob_start();105 106	$exports = array( $dropdown_id, home_url() );107	?>108	<script>109	( ( [ dropdownId, homeUrl ] ) => {110		const dropdown = document.getElementById( dropdownId );111		function onSelectChange() {112			setTimeout( () => {113				if ( 'escape' === dropdown.dataset.lastkey ) {114					return;115				}116				// Only navigate if a valid term is selected (not the default "Select [taxonomy]" option)117				if ( dropdown.value && dropdown.value !== '-1' && dropdown instanceof HTMLSelectElement ) {118					const url = new URL( homeUrl );119					url.searchParams.set( dropdown.name, dropdown.value );120					location.href = url.href;121				}122			}, 250 );123		}124		function onKeyUp( event ) {125			if ( 'Escape' === event.key ) {126				dropdown.dataset.lastkey = 'escape';127			} else {128				delete dropdown.dataset.lastkey;129			}130		}131		function onClick() {132			delete dropdown.dataset.lastkey;133		}134		dropdown.addEventListener( 'keyup', onKeyUp );135		dropdown.addEventListener( 'click', onClick );136		dropdown.addEventListener( 'change', onSelectChange );137	} )( <?php echo wp_json_encode( $exports, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ); ?> );138	</script>139	<?php140	return wp_get_inline_script_tag(141		trim( str_replace( array( '<script>', '</script>' ), '', ob_get_clean() ) ) .142		"\n//# sourceURL=" . rawurlencode( __FUNCTION__ )143	);144}

Changelog

Introduced in 5.0.0. 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 7.1.0 tag, from src/wp-includes/blocks/categories.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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