Text Limiter Hook for ProcessWire - adds a new method summarize() to $page - add this code to site/ready.php

summarize-method-hook.php

<?
// usage: $page->summaroze($fieldName, $maxLength)
$wire->addHook('Page::summarize', function($event) {

  $fieldName = $event->arguments(0);
  if(!$fieldName) throw new WireException("No field provided");

  // get max length or use 300 as default if none provided
  $maxLength = (int) $event->arguments(1);
  if(!$maxLength) $maxLength = 300;

  $page = $event->object;
  $value = $page->get($fieldName);

  if(!strlen($value)) {
    // requested value is blank, nothing more to do
    $event->return = '';
    return;
  }

  // get beginning of value, without any HTML in it (if any)
  $value = mb_substr(strip_tags($value), 0, $maxLength);

  // if output formatting on, make sure value is entity encoded
  if($page->of()) $value = $event->sanitizer->entities1($value);

  if(strlen($value) >= $maxLength) {
    // limit length of returned value between words
    // by truncating to the last space character
    $value = substr($value, 0, strrpos($value, ' '));
    // append an ellipsis to indicate there is more
    $value .= '&hellip;';
  }

  $event->return = $value;
});