[site-reviews] Change sorting of a Query Loop block

/**
 * Changes the sorting of a Query Loop block
 *
 * To use, add one of the following classes to the Query Loop block (in the Advanced panel of the block settings):
 * - sort-by-average
 * - sort-by-ranking
 * - sort-by-reviews
 */
add_filter('pre_render_block', function ($prerender, $block) {
    if ('core/query' !== $block['blockName']) {
        return $prerender;
    }
    $sorting = [
        'sort-by-average' => '_glsr_average',
        'sort-by-ranking' => '_glsr_ranking',
        'sort-by-reviews' => '_glsr_reviews',
    ];
    if (empty($block['attrs']['className']) || !array_key_exists($block['attrs']['className'], $sorting)) {
        return $prerender;
    }
    $sortKey = $sorting[$block['attrs']['className']];
    add_filter('query_loop_block_query_vars', function ($query) use ($sortKey) {
        $query['meta_query'] = [
            'relation' => 'OR',
            ['key' => $sortKey, 'compare' => 'NOT EXISTS'], // this comes first!
            ['key' => $sortKey, 'compare' => 'EXISTS'],
        ];
        $query['orderby'] = 'meta_value_num';
        glsr_log($query);
        return $query;
    });
}, 10, 2);