WP_Theme_JSON::prepend_to_selector │ protected static │ WP 6.3.0

Prepends a sub-selector to an existing one.

Given the compounded $selector "h1, h2, h3" and the $to_prepend selector ".some-class " the result will be ".some-class h1, .some-class h2, .some-class h3".

Method of the class: WP_Theme_JSON{}

No Hooks.

Returns

String. The new selector.

Usage

$result = WP_Theme_JSON::prepend_to_selector( $selector, $to_prepend );

$selector(string) (required)

Original selector.

$to_prepend(string) (required)

Selector to prepend.

Changelog

WP_Theme_JSON::prepend_to_selector() WP Theme JSON::prepend to selector code ^{WP 7.1}

protected static function prepend_to_selector( $selector, $to_prepend ) {
	if ( ! str_contains( $selector, ',' ) ) {
		return $to_prepend . trim( $selector, " \t\n" );
	}

	/**
	 * Check for an opportunity to skip the more-costly selector splitting.
	 * This should be possible if there are no comments, strings, functions,
	 * URLs, escapes, or comment declaration openers (CDOs).
	 *
	 * Note that this means the fast-path will not apply for selectors like
	 * the following incomplete list:
	 *
	 *  - `[class ~= "wide"]`
	 *  - `.wp-block:is(.is-style-a, .is-style-b)`
	 *  - `:nth-child(1)`
	 *
	 * These syntax forms all present opportunities where a comma may not
	 * separate selectors. If none of the start characters are present,
	 * there should be no way for a comma to mean anything other than a
	 * comma token. The exception are syntax errors, which are not handled here.
	 *
	 * @see https://www.w3.org/TR/css-syntax-3/#parse-comma-separated-list-of-component-values
	 */
	if ( strlen( $selector ) === strcspn( $selector, '/\'"(<\\' ) ) {
		return $to_prepend . preg_replace( '~[ \t\n]*,[ \t\n]*~', ", {$to_prepend}", trim( $selector, " \t\n" ) );
	}

	$new_selectors = array();
	$selectors     = static::split_selector_list( $selector );
	foreach ( $selectors as $sel ) {
		$new_selectors[] = $to_prepend . $sel;
	}
	return implode( ', ', $new_selectors );
}