How to convert formSubmitting event to web component

Questions
,
1

Hi
I have a anguarjs work on controller which like

function customEditController($scope, editorState) {

  $scope.$on("formSubmitting", function () { ..}
}

so I can add logic or set value under formSubmitting event inside
how about do it on current Umbraco web component version ?
as I can’t any sample inside

Thank you