Ajax API for WP - setup for PSR4 autoload

ajax.js

	$.ajax({
            type : "post",
            dataType : 'json',
            url : connect.ajaxurl,
            data : ({ action: 'connect', nonce: nonce, method: requestedMethod, params: dataParams }),
              success: function(response) { 
                console.log( response );
              },
              error: function(x, t, m) {
                console.log(x + t + m);
              }
        });

Ajax_Controller.php

<?php
namespace Classes;

/*//////////////////////////////////////////////////////////////////////////////
================================================================================
	Ajax_Controller
	- registers, enqueues, localizes ajax js file
	- passes method and params to Ajax_Function_Suite();
	- returns $ajax_function_suite->respond() as JSON
	- don't forget nonce
================================================================================
//////////////////////////////////////////////////////////////////////////////*/

class Ajax_Controller {

	protected $method;
	protected $params = [];

	/**
	 *	Add $this->connect() to wp_ajax_nopriv & wp_ajax
	 *	Add script enqueue
	 */
	public function __construct () 
	{
		add_action( 'wp_ajax_nopriv_connect', array ( $this, 'connect' ) );
        	add_action( 'wp_ajax_connect', array ( $this, 'connect' ) );
        	add_action( 'wp_enqueue_scripts', array ( $this, 'scripts' ) );
	}

	/**
	 *	Register, enqueue and localize ajax.js script
	 *	Edit to you needs
	 */
	public function scripts ()
	{
        	wp_register_script( 'ajax', get_stylesheet_directory_uri() . '/assets/js/ajax.js', array( 'jquery' ), '1.0.0', true);
		wp_enqueue_script( 'ajax' );
		wp_localize_script( 'ajax', 'connect', array( 'ajaxurl' => admin_url( 'admin-ajax.php' ) ) );
	}

	/** 
	 *	Capture Ajax method request and return JSON
	 *	@param $_REQUEST['nonce']
	 *	@param $_REQUEST['method']
	 *	@param $_REQUEST['params']
	 *	@return JSON
	 */
	public function connect ()
	{	
		if( !wp_verify_nonce( $_REQUEST['nonce'], 'ajax_user_nonce' ) )
			exit('You shall not pass!');

		$this->method = (isset($_REQUEST['method']))
			? $_REQUEST['method']
			: null;

		$this->params = (isset($_REQUEST['params']))
			? $_REQUEST['params']
			: [];
		
		// initialize Ajax_Function_Suite obj
		$ajax_function_suite = new Ajax_Function_Suite();

		exit( 
			json_encode( 
				[$ajax_function_suite->respond( $this->method, $this->params )] 
				) 
			);
	}
}

?>

Ajax_Function_Suite.php

<?php
namespace Classes;

/*//////////////////////////////////////////////////////////////////////////////
================================================================================
	Ajax_Function_Suite
	- compares $method to known list of methods
	- match found, run method, return result
	- no match found, return list of known methods
	- add your methods at bottom
================================================================================
//////////////////////////////////////////////////////////////////////////////*/

class Ajax_Function_Suite {

	protected $params = [];
	protected $class_methods = [];

	/**
	 *	Create list of internal methods
	 */
	public function __construct () 
	{
		$this->class_methods = get_class_methods( 'Classes\Ajax_Function_Suite' );
	}

	/**
	 *	Is method in list, else return list of methods
	 *	@param $method - string to find the method to call
	 *	@param $params - data for method if need be
	 *	@return response back to Ajax_Controller
	 */
	public function respond ( $method, $params ) 
	{
		if( in_array( $method, $this->class_methods ) ) :
			$this->params = $params;
			return $this->{$method}();
		endif;

		if( ! in_array( $method, $this->class_methods ) )
			return $this->method_not_found_repond();

		if( $method === null )
			return $this->method_not_found_repond();
	}

	/**
	 *	Return list of known methods
	 *	@return array
	 */
	protected function method_not_found_repond ()
	{
		return $this->class_methods;
	}
}