OOP · Inheritance · Mother & Calf
Inheritance in WordPress
Extend core base classes — reuse behavior, override only what changes.
WordPress is built on inheritance: widgets extend WP_Widget, REST endpoints extend WP_REST_Controller, customizers extend WP_Customize_Control. Child classes inherit boilerplate from core and focus on your plugin’s unique output — caching, markup, or query logic.
Core concept
A child class gets methods and properties from its parent. Override hooks like widget() or render_block() while shared utilities — caching, asset loading, sanitization — live in a base class inside your plugin suite.
WordPress core examples
- WP_Widget — sidebar widgets: form, update, and front-end output.
- Walker_Nav_Menu — customize menu HTML without rewriting walkers from scratch.
- WP_Customize_Control — Customizer fields with shared enqueue and JSON logic.
- WP_Block — block type registration inherits render callbacks from block.json.
Base widget with shared cache
Php
class Base_Widget extends WP_Widget {
protected function cache( string $output ): void {
set_transient( $this->id, $output, HOUR_IN_SECONDS );
}
}
class Popular_Posts extends Base_Widget {
public function widget( $args, $instance ) {
$posts = get_posts( [ 'orderby' => 'comment_count', 'numberposts' => 5 ] );
$html = $this->render_posts( $posts );
$this->cache( $html );
echo $html; // phpcs:ignore WordPress.Security.EscapeOutput
}
}The 4WP plugin suite uses the same pattern: a shared base in 4wp-bundle-core or module base classes so each addon only implements its specific feature.