napi is promise

napi_status napi_is_promise(napi_env env,
                            napi_value value,
                            bool* is_promise);

• [in] env: The environment that the API is invoked under.
• [in] value: The value to examine
• [out] is_promise: Flag indicating whether promise is a native promise object (that is, a promise object created by the underlying engine).