[WordPress] On Immutable Values in WordPress Plugins

00-main-plugin.php

<?php

class Main_Plugin {

  const ACME_API_KEY = '123456789';
  
  public function init() {
    
    $helper = new Helper_Class();
    $helper->render_acme_data( self::ACME_API_KEY );
  }
}

01-helper-class.php

<?php

class Helper_Class {

  public function render_acme_data( string $api_key ) {
    
    $canvas_url = 'https://url-for-canvas.com?api_key=' . $api_key;
    $canvas = new Canvas( $canvas_url );
  
    $canvas->draw();
  }
}