Client event iterator returns proxy events breaking applications that exepect structuredClone to work

[muniter]

Environment

orpc@1.17.11, node 24

Reproduction

Simply have a procedure that's an event iterator: https://orpc.unnoq.com/docs/event-iterator or use the recommended ai sdk integration https://orpc.unnoq.com/docs/integrations/ai-sdk#ai-sdk-integration and console.log the parts

      for await (const part of e) {
        console.log(part);
      }

You will see Proxy(Object) {type: 'start', messageMetadata: {…}, messageId: 'smsg-xYxxCOuD2sKB00wg'}

If you want to trigger an error using the ai sdk just write a data part using the UI writer.

         writer.write({
            type: "data-suggested-action",
            data: {
              type: "something",
            },
          });

Describe the bug

Returning proxy objects instead of plain objects causes issues in downstream consumers who expect a stream of plain objects.

Right now the AI SDK sometimes calls structuredClone on the messages (seems like when it gets data parts) and structure cloning a proxy throws an error.

Stack trace:

chat-component.tsx:158 DataCloneError: Failed to execute 'structuredClone' on 'Window': #<Object> could not be cloned.
    at ReactChatState.snapshot (@ai-sdk_react.js?v=f8f26246:4058:32)
    at ReactChatState.replaceMessage (@ai-sdk_react.js?v=f8f26246:4053:14)
    at write (@ai-sdk_react.js?v=f8f26246:2818:28)
    at @ai-sdk_react.js?v=f8f26246:2002:17
    at @ai-sdk_react.js?v=f8f26246:2811:17
    at Array.<anonymous> (@ai-sdk_react.js?v=f8f26246:2087:17)
    at SerialJobExecutor.processQueue (@ai-sdk_react.js?v=f8f26246:2078:26)
    at @ai-sdk_react.js?v=f8f26246:2093:17
    at new Promise (<anonymous>)
    at SerialJobExecutor.run (@ai-sdk_react.js?v=f8f26246:2084:12)

Overall I think the right approach is for the orpc client to not return proxy objects in the event iterator, given event iterator is the only option we have to send streams keeping things as plain as possible seems to be for the best to avoid compatibility issues with other libraries.

Additional context

No response

Logs

[dosubot]

Hi @muniter! I'm Dosu and I’m helping the orpc team.

The orpc client event iterator wraps streamed events in Proxy objects on the client side, likely to enable runtime features like change tracking or metadata access. This design breaks compatibility with consumers that expect plain objects, especially when using APIs like structuredClone, which cannot clone Proxy objects and throws a DataCloneError (example). There is currently no configuration or documented workaround to disable Proxy wrapping in the event iterator; the default behavior is to return Proxy objects, and this is not addressed in existing tickets or documentation.

If you need plain objects for downstream compatibility, you would need to manually unwrap the Proxy objects after receiving them, but this approach is not documented or officially recommended in the codebase. The issue is an undocumented edge case in the current orpc ecosystem.

To reply, just mention @dosu.

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[dinwwwh]

Let's try this PR: https://github.com/unnoq/orpc/pull/979 - hope can solve this problem without break anything

[muniter]

Thanks!