plugin.php

<?php

declare(strict_types=1);

namespace Flextype\Plugin\ReadingTime {

    use Twig\TwigFunction;

    /**
     * Get reading time
     *
     * @return string
     */
     function readingTime(string $content, array $options = []): string
     {
         $defaults = [
           'minute'              => 'minute',
           'minutes'             => 'minutes',
           'second'              => 'second',
           'seconds'             => 'seconds',
           'format'              => '{minutes_count} {minutes_label}, {seconds_count} {seconds_label}',
           'format.alt'          => '{seconds_count} {seconds_label}',
           'format.alt.enable'   => false
         ];

         $options      = array_merge($defaults, $options);
         $words        = str_word_count(strip_tags($content));
         $minutesCount = floor($words / 200);
         $secondsCount = floor($words % 200 / (200 / 60));
         $minutesLabel = ($minutesCount <= 1) ? $options['minute'] : $options['minutes'];
         $secondsLabel = ($secondsCount <= 1) ? $options['second'] : $options['seconds'];

         $replace      = [
           'minutes_count' => $minutesCount,
           'minutes_label' => $minutesLabel,
           'seconds_count' => $secondsCount,
           'seconds_label' => $secondsLabel,
         ];

         if ($minutesCount < 1 and $options['format.alt.enable'] === true) {
             $result = $options['format.alt'];
         } else {
             $result = $options['format'];
         }

         foreach ($replace as $key => $value) {
             $result = str_replace('{' . $key . '}', $value, $result);
         }

         return $result;
     }

    // Twig: {{ readingTime() }}
    flextype('twig')->addFunction(new TwigFunction('readingTime', fn (string $content, array $options = []) => readingTime($content, $options)));
}