A better version of our code to change the theme's stylesheet URL to the minified one.

asset-helpers.php

<?php

// code left out for brevity

add_filter( 'stylesheet_uri', 'change_theme_stylesheet_uri_to_min_version', 9999, 2 );
/**
 * Change the theme's stylesheet URI to minified version when not
 * in development/debug mode.
 *
 * @since 1.0.0
 *
 * @param string $stylesheet_uri Stylesheet URI for the current theme/child theme.
 * @param string $stylesheet_dir_uri Stylesheet directory URI for the current theme/child theme.
 *
 * @return string
 */
function change_theme_stylesheet_uri_to_min_version( $stylesheet_uri, $stylesheet_dir_uri ) {
	if ( site_is_in_debug_mode() ) {
		return $stylesheet_uri;
	}

	$minified_stylesheet_filename = '/style.min.css';

	if ( ! file_exists( get_stylesheet_directory() . $minified_stylesheet_filename ) ) {
		return $stylesheet_uri;
	}

	return $stylesheet_dir_uri . $minified_stylesheet_filename;
}