TinyMCE 5 Preview: Create new UI controls by extending existing ones

In Tinymce 4.x it is possible to create new UI controls by extending existing controls, eg:

var DataList = tinymce.ui.ComboBox.extend({
    init: function() {
         this._super();
    },
    value: function(value) {
        this._super(value);
    }
});
tinymce.ui.Factory.add('DataList', DataList);

but this does not appear to be possible in Tinymce 5, as the UI controls are not exposed in the API.

Is there another way this is done in Tinymce 5?

[ryandemmer]

You’re right, the intention of the new UI is that controls are not exposed in the API directly.

The aim is to provide flexible components that don’t need to be extended, making it easier to create dialogs that adjust to the active skin

That makes the UI less useful, as it restricts developers to the rather limited set of controls that you create an maintain, which are suitable for only simple dialogs. It also prevents developers from creating new controls for the toolbar, or adding features to existing ones.

Can you tell us more about why you need to extend controls?

Quite simply because the UI, in its present form and in Tinymce 5, does not provide the controls I require to accomplish the tasks that I need them to. Over quite a long period of time, I have created and tested a number of controls to suit my purposes.

Here is an example of some of the controls I have created in use:

[mdgilene]

Is this issue dead? Seems like custom UI components is a massive missing feature here. This holds back developing advanced plugins with complex UIs.