rwsdk/dist/runtime/render/normalizeActionResult.js

Build fast, server-driven webapps on Cloudflare with SSR, RSC, and realtime

// context(justinvdm, 24 Mar 2025): React flight limits chunks to 28 bytes, so we need to rechunk
// the stream to avoid losing data
function rechunkStream(stream, maxChunkSize = 28) {
    const reader = stream.getReader();
    return new ReadableStream({
        async pull(controller) {
            let buffer = new Uint8Array(0);
            try {
                while (true) {
                    const { done, value } = await reader.read();
                    if (done && buffer.length === 0) {
                        controller.close();
                        return;
                    }
                    if (value) {
                        buffer = new Uint8Array([...buffer, ...value]);
                    }
                    while (buffer.length >= maxChunkSize || (done && buffer.length > 0)) {
                        const chunk = buffer.slice(0, maxChunkSize);
                        buffer = buffer.slice(maxChunkSize);
                        controller.enqueue(chunk);
                    }
                    if (done) {
                        controller.close();
                        return;
                    }
                }
            }
            catch (error) {
                controller.error(error);
            }
        },
    });
}
export const normalizeActionResult = (actionResult) => {
    if (actionResult instanceof Response) {
        return {
            __rw_action_response: {
                status: actionResult.status,
                headers: {
                    location: actionResult.headers.get("location"),
                },
            },
        };
    }
    if (actionResult instanceof ReadableStream) {
        return rechunkStream(actionResult);
    }
    return actionResult;
};