passing Dart MediaStreamTrack to JavaScript

Question

I'm trying to make use of a third party JS library for some WebRTC functionality, and I would like to be able to use the MediaStreamTrack objects that I've already generated in my Dart-based audio application. The problem I'm running into is that the MediaStreamTrack object in Dart is not the native JavaScript MediaStreamTrack object, and when passed to JS via JsObject.callMethod(), it comes through with a DartObject type that doesn't reveal the expected methods and properties of a MediaStreamTrack, making it non-functional in the JS code. I first tried to work around this by constructing a new JsObject to pass into the JS code instead, and on it I mapped the necessary public methods/props back to the original Dart MediaStreamTrack's properties and methods. However, I've now run into a spot where the JS code constructs a new MediaStream object, passing to its constructor the MediaStreamTrack it expects me to supply. And so things blow up when the JS code tries to create the MediaStream and gets this JsObject that isn't a real JS MediaStreamTrack.

I'm not sure what else I can try. I'm imagining that Dart classes must essentially "wrap" these native MediaStream and MediaStreamTrack objects. And I thought there might be some way to access those underlying objects to use in the JS code. But I haven't found anything along those lines and suspect I'm headed in the wrong direction.

Answer 1

It turns out that I could work around this very simply by just adding a little JavaScript code to access the MediaStreamTrack object inside of the DartObject.

let audioTrack = dartObj[Object.getOwnPropertySymbols(dartObj)[0]];

I imagine this won't work for classes that are defined in Dart, but in this case, I think the Dart MediaStreamTrack class is essentially an interface for accessing the regular JavaScript MediaStreamTrack object. If someone understands this better, I'd appreciate clarification!