How to use the @ephox/boulder.FieldPresence.defaultedThunk function in @ephox/boulder

export interface DialogMenuButton extends BaseDialogButton {
  type: 'menu';
  text: Option;
  tooltip: Option;
  icon: Option;
  items: DialogToggleMenuItem[];
  onSetup: (api: DialogMenuButtonInstanceApi) => (api: DialogMenuButtonInstanceApi) => void;
}

export type DialogButton = DialogNormalButton | DialogMenuButton;

const baseButtonFields = [
  FieldSchema.field(
    'name',
    'name',
    FieldPresence.defaultedThunk(() => {
      return Id.generate('button-name');
    }),
    ValueSchema.string
  ),
  FieldSchema.optionString('icon'),
  FieldSchema.defaultedStringEnum('align', 'end', ['start', 'end']),
  FieldSchema.defaultedBoolean('primary', false),
  FieldSchema.defaultedBoolean('disabled', false)
];

export const dialogButtonFields = [
  ...baseButtonFields,
  FieldSchema.strictString('text')
];

const normalButtonFields = [