[WP] Generate an excerpt from any text

wp-trim-excerpt.php

<?php
/**
 * Generate an excerpt from any text.
 * 
 * @author Ivaylo Draganov <iv.draganov@druuf.com>
 * @note A modified version of core WP function wp_trim_excerpt
 * @param (string) $text - The text to trim.
 * @param (int) $words - The number of words to trim.
 * @return (string) The trimmed and filtered excerpt.
 */
function custom_trim_excerpt( $text = '', $words = '' ) {

  $raw_excerpt = $text;

	if ( $text ) {

		$text = strip_shortcodes( $text );

		$text = apply_filters('the_content', $text);
		$text = str_replace(']]>', ']]&gt;', $text);
		$excerpt_length = ( $words && is_numeric( $words ) ) ? absint( $words ) : apply_filters('excerpt_length', 55);
		$excerpt_more = apply_filters('excerpt_more', ' ' . '[...]');
		$text = wp_trim_words( $text, $excerpt_length, $excerpt_more );
	}

	return apply_filters('wp_trim_excerpt', $text, $raw_excerpt);
}