This is a demonstration project for developers who want to build front-end interfaces that communicate with a content management system's REST API using only modern, native JavaScript. It provides a practical reference for implementing clean, library-free API interactions, moving away from dependencies like jQuery.

• Native JavaScript Implementation: Uses the standard fetch API and ES6+ syntax, eliminating the need for external HTTP libraries and promoting modern development practices.
• Complete Endpoint Example: Includes fully documented PHP code for registering a secure REST API endpoint within the CMS, including argument validation.
• Access Control Patterns: Demonstrates different permission callback methods to restrict endpoint access to all users, logged-in users, or specific user roles.
• Secure Nonce Handling: Shows the correct method for generating and passing authentication nonces in request headers to maintain security for state-changing operations.
• Practical Data Flow: The demo plugin features a working shortcode that increments a number, illustrating the complete request and response cycle between the JavaScript client and the server-side callback.