Replacing window.confirm() with jQuery UI dialog confirm in entwine on admin form submit

SS3

On the admin Newsletter interface, how to replace form submit confirm window.confirm() with jQuery UI dialog confirm in entwine?

window.confirm() is a blocking method, so this._super(e) after it will be valid, but this._super(e) inside click callback of a jQuery UI dialog button is not since the onclick has already returned.

...
$.entwine('ss', function($) {
		$('#action_doSend').entwine({
			onclick: function(e) {
				var message = 'Are you sure you want to send this newsletter?';
				if (confirm(message)) {
					this._super(e);
				} else {
					e.preventDefault();
					return false;
				}
...

Tried this

...
	let self;
	$.entwine('ss', function($) {
		$('#action_doSend').entwine({
			onclick: function(e) {
				self = this;
				$( "#dialog-confirm-send" ).dialog({
					resizable: false,
					height: "auto",
					width: 400,
					modal: true,
					buttons: {
						"Send newsletter": _ => {
							self._super(e);
						},
						Cancel: function() {
							$(this).dialog( "close" );
						}
					}
				});
...