Custom SelectEntryFactory to allow optgroups

Developers Modeler
1

I am using a properties panel with extended properties. Some properties are dropdown lists (select). For that I am using entryFactory.selectBox, which works fine, but I would like to use optgroups inside my select elements to categorize my select options like in this example:

<label for="cars">Choose a car:</label>
<select name="cars" id="cars">
  <optgroup label="Swedish Cars">
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
  </optgroup>
  <optgroup label="German Cars">
    <option value="mercedes">Mercedes</option>
    <option value="audi">Audi</option>
  </optgroup>
</select>

How can I either extend SelectEntryFactory to be able to do this, or extend EntryFactory to use a custom GroupedSelectEntryFactory?

2

As you already said, creating your own custom entry factory with the existing SelectEntryFactory as an inspiration would be the best way to achieve what you want.

So far, I don’t know about any examples for optgroups factories.