wikimedia/mediawiki-extensions-MobileFrontend

<?php

namespace MobileFrontend\Transforms\Utils;

/**
 * Simple utility for working with html classes as with set
 */
class HtmlClassUtils {
    /**
     * Parse html class string into set (array of string=>bool) where key is class name
     * and values is always true
     *
     * @param string $classAttr raw `class` attribute's string retrieved from html
     *
     * @return array
     */
    public static function parseClassString( string $classAttr ): array {
        $classes = preg_split( '/\s+/', $classAttr, -1, PREG_SPLIT_NO_EMPTY );
        return array_fill_keys( $classes, true );
    }

    /**
     * Forms raw html `class` string from set of classes. Set is a key-value array where
     * key is class name and value is boolean that determines wheather this class should be
     * included to string or not.
     *
     *
     * @param array $classes set of classes that should be formed into string
     *
     * @return string
     */
    public static function formClassString( array $classes ): string {
        $enabled = array_filter(
            $classes,
            static function ( $enabled ) {
                return $enabled;
            }
        );
        return implode( ' ', array_keys( $enabled ) );
    }

    /**
     * Filters set of classes by list of allowed classes
     *
     * @param array $classes key-value array of html classes
     * @param string[] $allowedClasses list of allowed classes
     * @param string[] $additional list of additional styles should be added in front of list
     *
     * @return array
     */
    public static function filterAllowedClasses( array $classes, array $allowedClasses, array $additional ): array {
        return array_fill_keys( $additional, true ) + array_intersect_key(
            $classes,
            array_fill_keys( $allowedClasses, true )
        );
    }
}