WordPress ajax skeleton

plugin.php

<?php
/*
Plugin Name: My Plugin
Plugin URI: https://deeb.me
Description: 10 ways to peel an orange
*/
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

function StartItUp() {
	return new MyPluginClass();
}

add_action( 'init', 'StartItUp' );

class MyPluginClass {

	function __construct() {
		add_action( 'wp_enqueue_scripts', array( $this, 'load_scripts' ) );
		add_action( 'wp_ajax_myplugin', array( $this, 'ajax_callback_myplugin_function' ) );
	}
	
	public function load_scripts() {
	  wp_register_script( 'myplugin',
			plugins_url( 'script.js', __FILE__ ),
			array( 'jquery' )
		);
		wp_localize_script( 'myplugin', 'params', array(
			'ajaxurl' => admin_url( 'admin-ajax.php' )
		) );
		wp_enqueue_script( 'myplugin' );
  }

    function ajax_callback_myplugin_function() {
        if ( check_ajax_referer( '_the_nonce', 'security' ) ) {
			$somevar = $_POST['var_from_ajax_post'];

			if ( $somevar === 'false' ) {
			  wp_send_json_success( array( 'something' => 12, 'message' => 'AOK' ) );
			} else {
			  wp_send_json_error();
			}
		}
    }
    
    function add_click_link() {
        $ajax_nonce = wp_create_nonce( "myplugin" );
        $link       = '<a href="#" class="some-link-class" id="myclicker" '
				    . 'data-nonce="' . $ajax_nonce . '" data-somevar="' . $varX . '">Link</a>';
		return $link;
	}
}

script.js

jQuery(document).ready(function ($) {
    $('#myclicker').on('click', function (e) {
        e.preventDefault();
        var data = {
            action: 'myplugin',
            security: $(this).data('nonce'),
            var_from_ajax_post: $(this).data('somevar'),
        };
        $.post(params.ajaxurl, data, function (response) {
            $('#myclicker')
                .data('somevar', response.data.something)
                .text(response.data.message);
        });
    });

});