Get trimmed excerpt (by word) in WordPress

get_trimmed_excerpt.php

<?php
function get_trimmed_excerpt($maxChars = 160, $appendingString = '...', $default_excerpt = "Default page description.") 
{
    if( !is_single() && !is_page() )
    return $default_excerpt;
    
    the_post();
        
    $content = substr(get_the_excerpt(), 0, $maxChars);
    $content = strip_tags($content);
    $pos = strrpos($content, " ");
    
    if ($pos > 0) {
        $content = substr($content, 0, $pos);
    }
    
    $result = $content.$appendingString;
    
    rewind_posts();
    
    return $result;
}