Debugging drupalSettings

To see what will drupalSettings output you can put console log in drupalSettingsLoader.js  and this will give you info what is present in drupalSettings vars that is drupal pushing to JS 

  if (settingsElement !== null) {
    window.drupalSettings = JSON.parse(settingsElement.textContent);
    console.log(window.drupalSettings);
  }

you can also always call console.log (drupalSettings); in browser console and check out what is in.