How to get the values of controls in popup jira addon

[Nguyen Quach]

I'm making a Jira add-on, which will show a popup allow end user enter/input the content on this popup.

I'm using React app and atlaskit UI to add control/components

I would like to make the Atlasian API call, to post the data, I can listen the on submit event as following script

<script>
 AP.events.on('dialog.submit', function (e) {
 alert('submit button was clicked!');
 console.log(e.target.value);
 e.preventDefault();
});
</script>

I do not know, how can I get the value on the popup such as: text field, editor or datetime control, everyone please advice 

and how to validate the popup submission?

Thanks