mix.php

<?php

/**
 * Gets the path to a versioned Mix file in a theme.
 *
 * Use this function if you want to load theme dependencies. This function will cache the contents
 * of the manifest files for you.
 *
 * If you want to use mix in a child theme, use `mix_child()`.
 * If you want to use mix outside of your theme folder, you can use `mix_any()`.
 *
 * Inspired by <https://www.sitepoint.com/use-laravel-mix-non-laravel-projects/>.
 *
 * @since 1.0.0
 *
 * @param string $path The relative path to the file.
 * @param string $args {
 *     Optional. An array of arguments for the function.
 *
 *     @type bool   $is_child           Whether to check the child directory first. Default `false`.
 *     @type string $manifest_directory Custom relative path to manifest directory. Default `build`.
 * }
 *
 * @return string The versioned file URL.
 */
function mix( $path, $args = [] ) {
	// Manifest content cache.
	static $manifests = [];

	/**
	 * Backwards compatibility.
	 *
	 * @todo Remove in 2.x
	 */
	if ( is_string( $args ) ) {
		$args = [
			'manifest_directory' => $args,
		];
	}

	$defaults = [
		'is_child'           => false,
		'manifest_directory' => 'build',
	];

	/**
	 * Filters the default arguments used for the mix function
	 *
	 * @since 1.2.0
	 *
	 * @param array $defaults An array of default values.
	 */
	$defaults = apply_filters( 'theme/mix/args/defaults', $defaults );

	$args = wp_parse_args( $args, $defaults );

	$manifest_directory = $args['manifest_directory'];

	if ( $args['is_child'] ) {
		$base_path = trailingslashit( get_theme_file_path() );
	} else {
		$base_path = trailingslashit( get_parent_theme_file_path() );
	}

	$manifest_path = $base_path . trailingslashit( $manifest_directory ) . 'mix-manifest.json';

	// Bailout if manifest couldn’t be found.
	if ( ! file_exists( $manifest_path ) ) {
		return $base_path . $path;
	}

	if ( ! isset( $manifests[ $manifest_path ] ) ) {
		// @codingStandardsIgnoreLine
		$manifests[ $manifest_path ] = json_decode( file_get_contents( $manifest_path ), true );
	}

	$manifest = $manifests[ $manifest_path ];

	// Remove manifest directory from path.
	$path = str_replace( $manifest_directory, '', $path );
	// Make sure there’s a leading slash.
	$path = '/' . ltrim( $path, '/' );

	// Bailout with default theme path if file could not be found in manifest.
	if ( ! array_key_exists( $path, $manifest ) ) {
		if ( $args['is_child'] ) {
			return get_theme_file_uri( $path );
		}

		return get_parent_theme_file_uri( $path );
	}

	// Get file URL from manifest file.
	$path = $manifest[ $path ];
	// Make sure there’s no leading slash.
	$path = ltrim( $path, '/' );

	if ( $args['is_child'] ) {
		$file = trailingslashit( $manifest_directory ) . $path;

		/**
		 * We don’t use get_theme_file_uri(), because that function uses file_exists() to check if a
		 * file exists. If we pass in a full path including an ?id URL parameter, the file_exists()
		 * check will fail.
		 */
		$url = get_stylesheet_directory_uri() . '/' . $file;

		/**
		 * Pass in the URL to the theme_file_uri filter, because with the line above, we simulate
		 * the same functionality as get_theme_file_uri(). This should improve compatibility,
		 * because we use get_theme_file_uri() and get_parent_theme_file_uri() everywhere else.
		 *
		 * @see get_theme_file_uri()
		 */
		return apply_filters( 'theme_file_uri', $url, $file );
	}

	return get_parent_theme_file_uri( trailingslashit( $manifest_directory ) . $path );
}

/**
 * Gets the path to a versioned Mix file in a child theme.
 *
 * Similar to `mix()`, but tries to load a file from the child theme first.
 *
 * @since 1.2.0
 *
 * @param string $path The relative path to the file.
 * @param string $args {
 *     Optional. An array of arguments for the function.
 *
 *     @type bool   $is_child           Whether to check the child directory first. Default `false`.
 *     @type string $manifest_directory Custom relative path to manifest directory. Default `build`.
 * }
 *
 * @return string The versioned file URL.
 */
function mix_child( $path, $args = [] ) {
	$args = wp_parse_args( $args, [
		'is_child' => true,
	] );

	return mix( $path, $args );
}

/**
 * Gets the path to a versioned Mix file outside of your theme folders.
 *
 * The difference to the `mix()` function is that for this function, you need to provide the
 * absolute paths to the file and the manifest directory. The benefit is that it’s more versatile
 * and that you can use it for functionality that might not live in a theme, but in a plugin, vendor
 * packages or in a symlinked package.
 *
 * @since 1.1.0
 *
 * @param string $path               The full path to the file.
 * @param string $manifest_directory The full path to the manifest directory.
 * @param string $manifest_name      Optional. The name of the manifest file in
 *                                   `$manifest_directory`. Default
 *                                   `mix-manifest.json`.
 *
 * @return string The versioned file URL.
 */
function mix_any( $path, $manifest_directory, $manifest_name = 'mix-manifest.json' ) {
	$file_url = str_replace(
		trailingslashit( ABSPATH ),
		trailingslashit( site_url() ),
		$path
	);

	$manifest_path = trailingslashit( $manifest_directory ) . $manifest_name;

	// Bailout with file URL if manifest couldn’t be found.
	if ( ! file_exists( $manifest_path ) ) {
		return $file_url;
	}

	// @codingStandardsIgnoreLine
	$manifest       = json_decode( file_get_contents( $manifest_path ), true );
	$manifest_entry = str_replace( $manifest_directory, '', $path );

	// Make sure there’s a leading slash.
	$manifest_entry = '/' . ltrim( $manifest_entry, '/' );

	// Bailout with file URL could not be found in manifest.
	if ( ! array_key_exists( $manifest_entry, $manifest ) ) {
		return $file_url;
	}

	$file_path = $manifest[ $manifest_entry ];
	// Make sure there’s a leading slash.
	$file_path = '/' . ltrim( $file_path, '/' );

	// Add hash and return.
	return str_replace( $manifest_entry, $file_path, $file_url );
}