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WordPress

block_core_navigation_set_overlay_image_fetch_priority( string $overlay_blocks_html ): string

Since
7.0.0
Source
wp-includes/blocks/navigation.php:1198
Sets fetchpriority="low" on all IMG tags within the navigation overlay.

Description

Images in the overlay are hidden until the menu is opened, so they should not compete with any actual LCP element image on the page.

Compatibility

WordPress
since 7.0.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in 2 of the 5 tracked releases, added in 7.0.0, and compiles on PHP 7.4 through 8.6-dev.

Parameters

$overlay_blocks_htmlstring
The rendered HTML of the overlay blocks.

Return value

string
Modified HTML with fetchpriority="low" on all IMG tags.

Performance profile

How much work a call to block_core_navigation_set_overlay_image_fetch_priority() 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
Scales with input

The body loops, so the work grows with what you pass in.

Instructions
14

Executed per call on PHP 8.5. The body compiles to 18.

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 one call costs · 1 distinct outcome

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

WhenInstructionsCalls it makes
!->next_tag()14->next_tag(), ->get_updated_html()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 18 instructions, 14 executed per call, 1 branch. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 1

Used by · 1

Source code

View on Trac View on GitHub 

function block_core_navigation_set_overlay_image_fetch_priority( string $overlay_blocks_html ): string {	$tags = new WP_HTML_Tag_Processor( $overlay_blocks_html );	while ( $tags->next_tag( 'IMG' ) ) {		$tags->set_attribute( 'fetchpriority', 'low' );	}	return $tags->get_updated_html();}

Changelog

Introduced in 7.0.0. Unchanged from 7.0.4 through 7.1.0.

  1. 7.0.4
  2. 7.1.0

Signature, return type and hooks compared across 2 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/blocks/navigation.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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