Opening Hours extension showing a custom message on mondays

opening-hours-custom-text-on-mondays.php

<?php

use OpeningHours\Module\Shortcode\IsOpen;
use OpeningHours\Util\Dates;

add_filter('op_shortcode_attributes', function (array $attributes, $shortcode) {
  if ($shortcode instanceof IsOpen && (int) Dates::getNow()->format('w') === 1) {
    $attributes['text'] = 'Custom monday message';
    $attributes['classes'] = ''; // Remove open / closed styles
  }

  return $attributes;
}, 10, 2);