kurento-client (v7.x) fails to create MediaElement from external module (SyntaxError: Unknown type ...)

[DiegoRetamalPacheco]

When attempting to create an instance of a MediaElement defined in a custom, external Kurento module using kurento-client (JavaScript client for Node.js, versions 7.x tested), the operation fails with a SyntaxError: Unknown type '[object Object]' or SyntaxError: Unknown type '.' after direct lookup and hierarchy check. This occurs even though:

Kurento Media Server (KMS) successfully loads the external module on startup (confirmed via KMS logs).

The kurento-client can successfully create standard MediaElement types like MediaPipeline, WebRtcEndpoint, and even standard filters like FaceOverlayFilter from the same pipeline object.

The issue persists across different Node.js versions (14, 16, 18 tested) and specific kurento-client versions (7.0.0, 7.2.0, ^7.1.0).

This suggests a potential bug within kurento-client's mechanism for handling or registering types from external modules.

2025-04-02 10:39:43 setKurentoElements Error: SyntaxError: Unknown type 'customopencv.CustomOpenCV' after direct lookup and hierarchy check
2025-04-02 10:39:43 at getConstructor (/node_modules/kurento-client/lib/MediaObjectCreator.js:96:19)
2025-04-02 10:39:43 at createConstructor (/node_modules/kurento-client/lib/MediaObjectCreator.js:117:21)
2025-04-02 10:39:43 at createMediaObject (/node_modules/kurento-client/lib/MediaObjectCreator.js:183:23)
2025-04-02 10:39:43 at MediaObjectCreator.create (/node_modules/kurento-client/lib/MediaObjectCreator.js:312:12)
2025-04-02 10:39:43 at Room.createCustomFilter (/Classes/RoomClass.js:673:39)
2025-04-02 10:39:43 at Room.setKurentoElements (/Classes/RoomClass.js:64:35)
2025-04-02 10:39:43 at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
2025-04-02 10:39:43 type: { params: {}, type: 'customopencv.CustomOpenCV' }
2025-04-02 10:39:43 }