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WP_Theme_JSON::is_valid_viewport_breakpoint_size( mixed $value ): bool

Since
7.1.0
Source
wp-includes/class-wp-theme-json.php:765
Checks whether a viewport breakpoint value is a safe CSS length.

Description

Viewport breakpoints are limited to numeric px, em, and rem lengths.
CSS functions, percentages, and other units are rejected because breakpoint values are interpolated into generated media queries.

Compatibility

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

Present in 1 of the 5 tracked releases, added in 7.1.0, and compiles on PHP 7.4 through 8.6-dev.

Parameters

$valuemixed
Value to check.

Return value

bool
Whether the value is valid.

Performance profile

How much work a call to WP_Theme_JSON::is_valid_viewport_breakpoint_size() 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
4–10

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 12.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

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

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 WP_Theme_JSON::is_valid_viewport_breakpoint_size() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always4–10none

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev124–102
8.5124–102
8.4124–1025 fewer instructions than PHP 8.3
8.3174–152
8.2174–152
8.1174–152
7.4174–152

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.

Source code

View on Trac View on GitHub 

	private static function is_valid_viewport_breakpoint_size( $value ) {		if ( ! is_string( $value ) ) {			return false;		} 		$value = trim( $value );		if ( '' === $value ) {			return false;		} 		return 1 === preg_match( '/^(?:\d+|\d*\.\d+)(?:px|em|rem)$/', $value );	}

Changelog

Introduced in 7.1.0.

Signature, return type and hooks compared across 1 parsed release.

About this page

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