check if field_date exists in node object before accessing it in entity metadata wrapper

fd.php
// check if field_date exists in node object before accessing it in entity metadata wrapper
if (!empty($vars['content']['field_date'])) {
  $wrapper = entity_metadata_wrapper('node', $vars['node']);
  $timestamp = $wrapper->field_date->value();
  $vars['last_action'][] = date('m/j/Y', $timestamp);
}

// Check if a field_date isset in an object
if(isset($meeting->field_date)) {
  $meeting_date = $meeting_wrapper->field_date->value();
}
else {
  $meeting_date = "";
}