wp_maybe_add_fetchpriority_high_attr( array $loading_attrs, string $tag_name, array $attr ): array

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This function’s access is marked private. This means it is not intended for use by plugin or theme developers, only in other core functions. It is listed here for completeness.

Determines whether to add fetchpriority='high' to loading attributes.

Parameters

$loading_attrsarrayrequired
Array of the loading optimization attributes for the element.
$tag_namestringrequired
The tag name.
$attrarrayrequired
Array of the attributes for the element.

Return

array Updated loading optimization attributes for the element.

Source

function wp_maybe_add_fetchpriority_high_attr( $loading_attrs, $tag_name, $attr ) {
	// For now, adding `fetchpriority="high"` is only supported for images.
	if ( 'img' !== $tag_name ) {
		return $loading_attrs;
	}

	if ( isset( $attr['fetchpriority'] ) ) {
		/*
		 * While any `fetchpriority` value could be set in `$loading_attrs`,
		 * for consistency we only do it for `fetchpriority="high"` since that
		 * is the only possible value that WordPress core would apply on its
		 * own.
		 */
		if ( 'high' === $attr['fetchpriority'] ) {
			$loading_attrs['fetchpriority'] = 'high';
			wp_high_priority_element_flag( false );
		}

		return $loading_attrs;
	}

	// Lazy-loading and `fetchpriority="high"` are mutually exclusive.
	if ( isset( $loading_attrs['loading'] ) && 'lazy' === $loading_attrs['loading'] ) {
		return $loading_attrs;
	}

	if ( ! wp_high_priority_element_flag() ) {
		return $loading_attrs;
	}

	/**
	 * Filters the minimum square-pixels threshold for an image to be eligible as the high-priority image.
	 *
	 * @since 6.3.0
	 *
	 * @param int $threshold Minimum square-pixels threshold. Default 50000.
	 */
	$wp_min_priority_img_pixels = apply_filters( 'wp_min_priority_img_pixels', 50000 );

	if ( $wp_min_priority_img_pixels <= $attr['width'] * $attr['height'] ) {
		$loading_attrs['fetchpriority'] = 'high';
		wp_high_priority_element_flag( false );
	}

	return $loading_attrs;
}

Changelog

VersionDescription
6.3.0Introduced.

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