TEC 3.x [event_category_link slug="x"] shortcode

/**
 * Handler for event_category_link shortcode.
 * Usage: [event_category_link slug="my-category-slug"]
 *
 * If the slug is invalid or isn't provided then it will
 * return empty.
 *
 * @param $args
 * @return string
 */
function event_category_link_shortcode($args) {
    // We need TribeEvents to have loaded and a slug to have been passed in
    if (!class_exists('TribeEvents')) return;
    if (empty($args) or !isset($args['slug'])) return;

    // Try to load the term, return empty if it can't be found
    $term = get_term_by('slug', $args['slug'], TribeEvents::TAXONOMY);
    if (!$term || !is_object($term)) return;

    // Get the link
    $url = TribeEvents::instance()->getLink('upcoming', false, $term->term_id);
    $link = '<a href="' . esc_attr($url) . '"> ' . esc_html($term->name) . ' </a>';

    return $link;
}

add_shortcode('event_category_link', 'event_category_link_shortcode');