Registers a short code that displays the most popular posts. (Helpful WordPress Plugin)

functions.php

<?php
/**
 * Place this code in the functions.php
 */

/**
 * Determines the content for the shortcode for the last best rated posts.
 * Example: [helpful_pro post_type="post" limit="5"]
 *
 * @param array $atts
 * 
 * @return string
 */
function register_helpful_shortcode( $atts ) {

	$defaults = [
		'post_type' => 'post',
		'limit'     => 5,
	];

	$atts = shortcode_atts( $defaults, $atts, 'helpful_pro' );

	$shortcodes = '';

	$limit = 5;

	if ( 5 !== $atts['limit'] && is_numeric( $atts['limit'] ) ) {
		$limit = intval( $atts['limit'] );
	}

	$args = [
		'post_type'      => $atts['post_type'],
		'posts_per_page' => $atts['limit'],
		'metakey'        => 'helpful-pro',
		'orderby'        => [ 'helpful-pro' => 'DESC' ],
	];

	$query = new WP_Query( $args );

	if ( $query->have_posts() ) {

		$shortcode .= '<ul>';

		while ( $query->have_posts() ) : $query->the_post();

			$post_id = get_the_ID();
			$pro     = helpful_get_pro( $post_id );
			update_post_meta( $post_id, 'helpful-pro', $pro );

			$shortcode .= sprintf(
				'<li><a href="%1$s">%2$s</a></li>',
				get_the_permalink(),
				get_the_title()
			);

		endwhile;

		$shortcode .= '</ul>';

		wp_reset_postdata();
	}

	return $shortcode;
}

/**
 * Register the shortcode.
 * Example: [helpful_pro post_type="post" limit="5"]
 */
add_shortcode( 'helpful_pro', 'register_helpful_shortcode' );

/**
 * Allows the use of shortcuts in widgets.
 */
add_filter( 'widget_text', 'do_shortcode' );