Asset versioning helpers and asset loader for Twenty Seventeen theme

asset-helpers.php

<?php
/**
 * Asset versioning helpers and asset loader
 *
 * @package     Twenty Seventeen
 * @since       1.0.0
 * @author      hellofromTonya
 * @link        https://KnowTheCode.io
 * @license     GNU-2.0+
 */

add_action( 'wp_enqueue_scripts', 'twentyseventeen_scripts' );
/**
 * Enqueue scripts and styles.
 */
function twentyseventeen_scripts() {
	$version_number = get_theme_version();
	$theme_dir      = get_stylesheet_directory();

	// Add custom fonts, used in the main stylesheet.
	wp_enqueue_style( 'twentyseventeen-fonts', twentyseventeen_fonts_url(), array(), null );

	// Theme stylesheet.
	wp_enqueue_style( 'twentyseventeen-style', get_stylesheet_uri(), array(), $version_number );

	// Load the dark colorscheme.
	if ( 'dark' === get_theme_mod( 'colorscheme', 'light' ) || is_customize_preview() ) {
		$asset_file = '/assets/css/colors-dark.css';

		wp_enqueue_style(
			'twentyseventeen-colors-dark',
			get_theme_file_uri( $asset_file ),
			array( 'twentyseventeen-style' ),
			get_asset_current_version_number( $theme_dir . $asset_file )
		);
	}

	// Load the Internet Explorer 9 specific stylesheet, to fix display issues in the Customizer.
	if ( is_customize_preview() ) {
		$asset_file = '/assets/css/ie9.css';

		wp_enqueue_style(
			'twentyseventeen-ie9',
			get_theme_file_uri( $asset_file ),
			array( 'twentyseventeen-style' ),
			get_asset_current_version_number( $theme_dir . $asset_file )
		);
		wp_style_add_data( 'twentyseventeen-ie9', 'conditional', 'IE 9' );
	}

	// Load the Internet Explorer 8 specific stylesheet.
	$asset_file = '/assets/css/ie8.css';

	wp_enqueue_style(
		'twentyseventeen-ie8',
		get_theme_file_uri( $asset_file ),
		array( 'twentyseventeen-style' ),
		get_asset_current_version_number( $theme_dir . $asset_file )
	);
	wp_style_add_data( 'twentyseventeen-ie8', 'conditional', 'lt IE 9' );

	// Load the html5 shiv.
	$asset_file = '/assets/js/html5.js';
	wp_enqueue_script(
		'html5',
		get_theme_file_uri( $asset_file ),
		array(),
		get_asset_current_version_number( $theme_dir . $asset_file )
	);
	wp_script_add_data( 'html5', 'conditional', 'lt IE 9' );

	$asset_file = '/assets/js/skip-link-focus-fix.js';
	wp_enqueue_script(
		'twentyseventeen-skip-link-focus-fix',
		get_theme_file_uri( $asset_file ),
		array(),
		get_asset_current_version_number( $theme_dir . $asset_file ),
		true
	);

	$twentyseventeen_l10n = array(
		'quote' => twentyseventeen_get_svg( array( 'icon' => 'quote-right' ) ),
	);

	if ( has_nav_menu( 'top' ) ) {
		wp_enqueue_script( 'twentyseventeen-navigation', get_theme_file_uri( '/assets/js/navigation.js' ),
			array( 'jquery' ), '1.0', true );
		$twentyseventeen_l10n['expand']   = __( 'Expand child menu', 'twentyseventeen' );
		$twentyseventeen_l10n['collapse'] = __( 'Collapse child menu', 'twentyseventeen' );
		$twentyseventeen_l10n['icon']     = twentyseventeen_get_svg( array(
			'icon'     => 'angle-down',
			'fallback' => true,
		) );
	}

	$asset_file = '/assets/js/global.js';
	wp_enqueue_script(
		'twentyseventeen-global',
		get_theme_file_uri( $asset_file ),
		array( 'jquery' ),
		get_asset_current_version_number( $theme_dir . $asset_file ),
		true
	);

	$asset_file = '/assets/js/jquery.scrollTo.js';
	wp_enqueue_script(
		'jquery-scrollto',
		get_theme_file_uri( $asset_file ),
		array( 'jquery' ),
		get_asset_current_version_number( $theme_dir . $asset_file ),
		true
	);

	wp_localize_script(
		'twentyseventeen-skip-link-focus-fix',
		'twentyseventeenScreenReaderText',
		$twentyseventeen_l10n
	);

	if ( is_singular() && comments_open() && get_option( 'thread_comments' ) ) {
		wp_enqueue_script( 'comment-reply' );
	}
}

/**
 * Get the theme's version.
 *
 * When in development/mode mode, it uses the style.css modification time.
 * Else, it grabs the version number from the stylesheet.
 *
 * @since 1.0.0
 *
 * @return string|int
 */
function get_theme_version() {
	if ( site_is_in_debug_mode() ) {
		return get_asset_current_version_number(
			get_stylesheet_directory() . '/style.css'
		);
	}

	$theme = wp_get_theme();

	return $theme->get( 'Version' );
}

/**
 * Get the specified asset file's current version number.
 * This function gets the file's modification time when
 * the site is in development/debug mode.
 *
 * @since 1.0.0
 *
 * @param $asset_file
 *
 * @return bool|int
 */
function get_asset_current_version_number( $asset_file ) {
	return filemtime( $asset_file );
}

/**
 * Checks if the site is in development/debug mode.
 *
 * @since 1.0.0
 *
 * @return bool
 */
function site_is_in_debug_mode() {
	if ( ! defined( 'SCRIPT_DEBUG' ) ) {
		return false;
	}

	return ( (bool) SCRIPT_DEBUG === true );
}

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;
}