How to use the netlify-cms-widget-object.previewComponent function in netlify-cms-widget-object

CMS.registerBackend('github', GitHubBackend);
CMS.registerBackend('gitlab', GitLabBackend);
CMS.registerBackend('bitbucket', BitbucketBackend);
CMS.registerBackend('test-repo', TestBackend);
/** Widgets */
CMS.registerWidget('string', NetlifyCmsWidgetString.controlComponent, NetlifyCmsWidgetString.previewComponent);
CMS.registerWidget('number', NetlifyCmsWidgetNumber.controlComponent, NetlifyCmsWidgetNumber.previewComponent);
CMS.registerWidget('text', NetlifyCmsWidgetText.controlComponent, NetlifyCmsWidgetText.previewComponent);
CMS.registerWidget('list', NetlifyCmsWidgetList.controlComponent, NetlifyCmsWidgetList.previewComponent);
CMS.registerWidget('markdown', NetlifyCmsWidgetMarkdown.controlComponent, NetlifyCmsWidgetMarkdown.previewComponent);
CMS.registerWidget('image', NetlifyCmsWidgetImage.controlComponent, NetlifyCmsWidgetImage.previewComponent);
CMS.registerWidget('file', NetlifyCmsWidgetFile.controlComponent, NetlifyCmsWidgetFile.previewComponent);
CMS.registerWidget('date', NetlifyCmsWidgetDate.controlComponent, NetlifyCmsWidgetDate.previewComponent);
CMS.registerWidget('datetime', NetlifyCmsWidgetDatetime.controlComponent, NetlifyCmsWidgetDatetime.previewComponent);
CMS.registerWidget('select', NetlifyCmsWidgetSelect.controlComponent, NetlifyCmsWidgetSelect.previewComponent);
CMS.registerWidget('object', NetlifyCmsWidgetObject.controlComponent, NetlifyCmsWidgetObject.previewComponent);
CMS.registerWidget('relation', NetlifyCmsWidgetRelation.controlComponent, NetlifyCmsWidgetRelation.previewComponent);
CMS.registerWidget('boolean', NetlifyCmsWidgetBoolean.controlComponent);
CMS.registerWidget('map', NetlifyCmsWidgetMap.controlComponent, NetlifyCmsWidgetMap.previewComponent);
/** MediaLibraries */
// CMS.registerMediaLibrary(uploadcare);
// CMS.registerMediaLibrary(cloudinary);
/** EditorComponents */
CMS.registerEditorComponent(image);

export default CMS;

import controlComponent from './ListControl';
import NetlifyCmsWidgetObject from 'netlify-cms-widget-object';

const previewComponent = NetlifyCmsWidgetObject.previewComponent;
const Widget = (opts = {}) => ({
  name: 'list',
  controlComponent,
  previewComponent,
  ...opts,
});

export const NetlifyCmsWidgetList = { Widget, controlComponent, previewComponent };
export default NetlifyCmsWidgetList;