Adding Custom Components/Control in bpmn form.js biulder tool

Dear Team,
I have .net core application where I implemented bpm form.js form-js

Now I want to add some custom components in the schema

Here is my working example:

<html>
<head>   
    <style>
        body, html {
            margin: 0;
            padding: 0;
            font-family: sans-serif;
        }

        #form {
            max-width: 100%;
        }
    </style>
</head>

<body>
    <div id="form"></div>
    <button id="customButton">Custom Button</button>
    <script type="application/form-schema">
        {
          "schemaVersion": 1,
          "exporter": {
            "name": "form-js",
            "version": "0.1.0"
          },
          
          "type": "default"
        }
    </script>

    <!--
      required editor script
    -->

    <script>
         document.getElementById('customButton').addEventListener('click', function ()
    {
            const schema = JSON.parse(
                document.querySelector('[type="application/form-schema"]').textContent
            );
            const schemsa = formEditor.saveSchema(schema);
            console.log('exported schema', schemsa);
    });


        const schema = JSON.parse(
            document.querySelector('[type="application/form-schema"]').textContent
        );

        const container = document.querySelector('#form');

        FormEditor.saveSchema({
            container,
            schema
        });
    </script>
</body>
</html>

AFAIK there is no extension mechanism for form-js yet. Check out this issue for progress: Support for custom elements · Issue #123 · bpmn-io/form-js · GitHub