Truncate text with PHP and CSS

truncate.css

/**
 * Text truncation
 *
 * Prevent text from wrapping onto multiple lines, and truncate with an
 * ellipsis.
 *
 * 1. Ensure that the node has a maximum width after which truncation can
 *    occur.
 * 2. Fix for IE 8/9 if `word-wrap: break-word` is in effect on ancestor
 *    nodes.
 */

.u-textTruncate {
  max-width: 100%; /* 1 */
  overflow: hidden !important;
  text-overflow: ellipsis !important;
  white-space: nowrap !important;
  word-wrap: normal !important; /* 2 */
}

truncate.php

<?php

function textTruncate($string = '', $widows = 2, $truncateClass = 'u-textTruncate')
{
    // Remove trailing whitespace
    $string = trim($string);

    // If html, split up each element and run textTruncate on them.
    // Only paragraphs and list items for now.
    if (substr($string, 0, 2) === '<p' || substr($string, 0, 3) === '<li') {
        $string = preg_replace_callback_array([
            '/(\<[p][^\>]*\>)(.*?)(\<\/[p]\>)/' => function ($matches) {
              return $matches[1] . textTruncate($matches[2]) . $matches[3];
            },
            '/(\<li[^\>]*\>)(.*?)(\<\/li\>)/' => function ($matches) {
              return $matches[1] . textTruncate($matches[2]) . $matches[3];
            }
        ], $string);

        return $string;
    }

    // Split words into array
    $split = explode(" ", str_replace('&nbsp;', " ", $string));
    $split_count = sizeof($split);

    // If less than 5 words; do not truncate
    if ($split_count < 5) {
        return $string;
    }

    // If last word is longer than 12 characters; do not truncate.
    if (strlen($split[$split_count - 1]) > 12) {
        return $string;
    }

    // If there are more words than allowed widows; truncate
    if ($split_count > $widows) {
        $words = $split[$split_count - 2] . ' ' . $split[$split_count - 1];

        // Skip numbers because they could be long with spaces like 1 000 000.
        if (!startsWithNumber($words) && endsWithNumber($words)) {
            $string = str_replace($words, '<span class="' . $truncateClass . '">' . $words . '</span>', $string);
        }
    }

    return $string;
}

function startsWithNumber ($str)
{
    return preg_match('/^\d/', $str) === 1;
}

function endsWithNumber ($str)
{
    return preg_match('/\d$/', $str) === 1;
}