mercury_editor-2.0.x-dev/source/js/sync-changes.js

((Drupal, once) => {
  function applyChanges(event) {
    const element = event.target;
    const ref = element.getAttribute('data-sync-changes');
    const value = element.value || element.textContent;
    const msg = {
      type: 'syncChanges',
      settings: {ref, value}
    };
    document.getElementById('me-preview').contentWindow.postMessage(msg);
  }
  Drupal.behaviors.mercuryEditorSyncChanges = {
    attach: function attach(context, settings) {
      once('me-close-builder', '[data-sync-changes]', context).forEach((e) => {
        e.addEventListener('input', applyChanges);
        e.addEventListener('change', applyChanges);
      });
    }
  }
})(Drupal, once)