code added to functions.php

add_action( 'wp_enqueue_scripts', function() {
    if ( is_page_template( 'custom-map_24hours.php' ) ) {
        wp_enqueue_style( 'leaflet', 'https://unpkg.com/leaflet@1.6.0/dist/leaflet.css', [], '1.6.0' );
        wp_enqueue_script( 'leaflet', 'https://unpkg.com/leaflet@1.6.0/dist/leaflet.js', [], '1.6.0', true );

        wp_enqueue_script( 'list_24hours', get_parent_theme_file_uri( 'js/list_24hours.js' ), ['jquery', 'leaflet'], '1.0', true );

        $locations = [];
        $query = new WP_Query( [
            'post_type' => 'action',
        ] );
        foreach ( $query->posts as $post ) {
// pick only 24 hours actions
            if ( rwmb_get_value('calendar', '', $post->ID) == '24hours') {

            $location            = rwmb_get_value( 'action-location', '', $post->ID );
//            $location['title']   = $post->post_title;
            $location['title']   = rwmb_get_value( 'action-title', '', $post->ID );
            $location['address'] = rwmb_get_value( 'action-address', '', $post->ID );
            $location['icon']    = rwmb_get_value( 'action-icon', '', $post->ID );
            $location['description']    = rwmb_get_value( 'action-description', '', $post->ID );
            $location['start']    = rwmb_get_value( 'action-start-date', '', $post->ID );
            $location['end']    = rwmb_get_value( 'action-end-date', '', $post->ID );
            $location['link']    = rwmb_get_value( 'action-url', '', $post->ID );
            $location['calendar']    = rwmb_get_value( 'calendar', '', $post->ID );
            $location['mediaembed']     = rwmb_get_value( 'mediaembed', '', $post->ID );
            $locations[]         = $location;
        }
        }
        wp_localize_script( 'list_24hours', 'Locations', $locations );
    }
} );