WasmGC structs and arrays are completely opaque to JS, which is why you're seeing an empty object { }
WasmGC structs and arrays are completely opaque to JS, which is why you're seeing an empty object { }. That also means that the only way to access their contents from JS is by calling exported Wasm functions that can do the accesses. There is broad interest in making this easier, but all the obvious solutions would be technically very challenging to implement in JS engines, so I wouldn't expect this to change soon.