Jquery push form ID to datalayer event

Question

I have the following script which pushes an event to the datalayer called 'form-submit':

$(document).on('frmFormComplete', function(event, form, response) {
  dataLayer.push({
    'event': 'form-submit'
  });
});

I want to be able to push the form ID name into the event. This is an example if my form ID was 'myform':

$(document).on('frmFormComplete', function(event, form, response) {
  dataLayer.push({
    'event': 'myform-form-submit'
  });
});

Is this possible? I've tried something like this but can't get it to work:

$(document).on('frmFormComplete', function(event, form, response) {
  var formId = $('form').attr('id');
  dataLayer.push({
    'event': 'formId.-form-submit'
  });
});