[WordPress] Trims text of spam comments on Admin→Comments→Spam down to a maximum of 42 characters. Will save you a heck of annoyance when you need to skim through spam comments. Because many of them tend to have looong paragraphs of text you don’t really wanna deal with; they are spam, after all.

trim-spam-comment-text.php

<?php
/**
 * Plugin Name: Trim Spam Comment Text
 * Description: Trims text of spam comments on <a href="/wp-admin/edit-comments.php?comment_status=spam">Admin→Comments→Spam</a> down to a maximum of 42 characters. Will save you a heck of annoyance when you need to skim through spam comments. Because many of them tend to have looong paragraphs of text you don’t really wanna deal with; they are spam, after all.
 * Version:     0.0.2
 * Author:      Caspar Hübinger
 * Author URI:  https://glueckpress.com/
 * Plugin URI:  https://gist.github.com/glueckpress/7316116faa491e09d199/
 * License: GNU General Public License v2 or later
 * License URI: http://www.gnu.org/licenses/gpl-2.0.html
 */

namespace Glck\Comments\Spam;

defined( 'ABSPATH' ) || exit;

add_filter( 'comment_text', __NAMESPACE__ . '\\comment_text', 10, 3 );

/**
 * Hide comment text when in spam list table.
 *
 * @param   string $comment_text Text of the current comment.
 * @param   object $comment      The comment object.
 * @param   array  $args         Optional. An array of arguments. Default: empty array.
 * @return  string               Filtered comment text
 */
function comment_text( $comment_text, $comment, $args = [] ) {

	if ( ! is_admin() ) {
		return $comment_text;
	}

	$screen = get_current_screen();

	// edit-comments.php?comment_status=spam
	if ( $screen->id === 'edit-comments'
	      && isset( $_GET[ 'comment_status' ] ) // avoid PHP notice on edit-comments.php
	      && $_GET[ 'comment_status' ] === 'spam' ) {

		// Limit text to 42 characters maximum, so we can get but a glimpse.
		$divider      = strlen( utf8_decode( $comment_text ) ) < 42 ? 42 : strpos( $comment_text, ' ', 42 );
		$trimmed      = substr( $comment_text, 0, $divider );
		$comment_text = sprintf( '%s [&#8230;]', $trimmed );
	}

	return $comment_text;
}