Function js::jsapi::JS_GetDataViewByteLength

pub unsafe extern "C" fn JS_GetDataViewByteLength(obj: *mut JSObject) -> u32

Return the byte length of a data view.

|obj| must have passed a JS_IsDataViewObject test, or somehow be known that it would pass such a test: it is a data view or a wrapper of a data view, and the unwrapping will succeed. If cx is nullptr, then DEBUG builds may be unable to assert when unwrapping should be disallowed.