Retrieves the data from an external object.

STDAPI_(JsErrorCode)
    JsGetExternalData(
    _In_ JsValueRef object,
    _Out_ void **externalData);

• object: The external object.
• externalData: The external data stored in the object. Can be null if no external data is stored in the object.

The code JsNoError if the operation succeeded, a failure code otherwise.