A catalog generator for WordPress.

catalog.php

<?php
/*
Plugin Name: Catelog
Description: Generates a dynamic page showing categories and their posts
Version: 0.1
Author: hxueh
Author URI: https://www.hxueh.net
*/

// Prevent direct access to the plugin file
if (!defined('ABSPATH')) {
    exit;
}
function catelog()
{
    $output = '<ul>';

    // Get all categories, ordered alphabetically
    $categories = get_categories(
        array(
            'orderby' => 'name',
            'order' => 'ASC'
        )
    );

    foreach ($categories as $category) {
        // add category url to output
        $output .= '<li><strong>Category:</strong> <a href="' . esc_url(get_category_link($category->term_id)) . '">' . esc_html($category->name) . '</a>';

        // Get posts for this category, ordered by creation time
        $posts = get_posts(
            array(
                'category' => $category->term_id,
                'orderby' => 'date',
                'order' => 'DESC',
                'numberposts' => -1,
            )
        );

        if ($posts) {
            $output .= '<ul>';
            foreach ($posts as $post) {
                $post_date = get_the_date('F j, Y', $post->ID);
                $output .= '<li>';
                $output .= '<a href="' . esc_url(get_permalink($post->ID)) . '">' . esc_html($post->post_title) . '</a>';
                $output .= ' - <span class="post-date">' . esc_html($post_date) . '</span>';
                $output .= '</li>';
            }
            $output .= '</ul>';
        }
        $output .= '</li>';
    }

    $output .= '</ul>';

    return $output;
}

add_shortcode('catelog', 'catelog');