# RenderToReadableStreamOptions

**Kind:** Interface

**Source:** [`src/jsx/dom/server.ts`](https://github.com/honojs/hono/blob/main/src/jsx/dom/server.ts#L32)

**Part of:** [Jsx](subsystem-src-jsx)

`RenderToReadableStreamOptions` configures how server-rendered JSX is emitted as a readable stream. It controls identifier and namespace settings, bootstrap scripts, chunking behavior, cancellation through an `AbortSignal`, and error handling.

## Properties

| Property | Type |
|---|---|
| `identifierPrefix` | `string` |
| `namespaceURI` | `string` |
| `nonce` | `string` |
| `bootstrapScriptContent` | `string` |
| `bootstrapScripts` | `string[]` |
| `bootstrapModules` | `string[]` |
| `progressiveChunkSize` | `number` |
| `signal` | `AbortSignal` |
| `onError` | `(error: unknown) => string | void` |

## Diagram

```mermaid
graph LR
  App[JSX application] --> Render[renderToReadableStream]
  Options[RenderToReadableStreamOptions] --> Render
  Options --> IDs[identifierPrefix]
  Options --> Namespace[namespaceURI]
  Options --> Scripts[Bootstrap scripts and modules]
  Options --> Stream[progressiveChunkSize]
  Options --> Abort[signal]
  Options --> Errors[onError]
  Render --> Output[ReadableStream]
```

## Usage

```ts
import { renderToReadableStream } from "react-dom/server";
import type { RenderToReadableStreamOptions } from "react-dom/server";

const controller = new AbortController();

const options: RenderToReadableStreamOptions = {
  identifierPrefix: "app-",
  namespaceURI: "http://www.w3.org/2000/svg",
  nonce: "request-nonce",
  bootstrapScriptContent: "window.__SSR_READY__ = true;",
  bootstrapScripts: ["/assets/client.js"],
  bootstrapModules: ["/assets/client.mjs"],
  signal: controller.signal,
  onError(error) {
    console.error("Server render failed:", error);
    return "render-error";
  },
};

const stream = await renderToReadableStream(<App />, options);

return new Response(stream, {
  headers: {
    "Content-Type": "text/html",
  },
});
```

## AI Coding Instructions

- Pass a stable `identifierPrefix` when multiple rendered roots can appear in the same document.
- Set `nonce` when the page uses a Content Security Policy that restricts inline scripts.
- Use either `bootstrapScripts` or `bootstrapModules` according to the client asset format being loaded.
- Pass a request-scoped `AbortSignal` so rendering stops when the client disconnects or the request is cancelled.
- Handle errors in `onError`; return a string when the renderer needs an error identifier, or return `void` after logging the error.

## How it works

`RenderToReadableStreamOptions` is the exported TypeScript interface for the optional second argument to `renderToReadableStream`; every member is optional. [src/jsx/dom/server.ts:32-42](src/jsx/dom/server.ts#L32-L42) [src/jsx/dom/server.ts:50-53](src/jsx/dom/server.ts#L50-L53)

Its declared members are:

- `identifierPrefix?: string`
- `namespaceURI?: string`
- `nonce?: string`
- `bootstrapScriptContent?: string`
- `bootstrapScripts?: string[]`
- `bootstrapModules?: string[]`
- `progressiveChunkSize?: number`
- `signal?: AbortSignal`
- `onError?: (error: unknown) => string | void`  
  [src/jsx/dom/server.ts:32-42](src/jsx/dom/server.ts#L32-L42)

At runtime, `renderToReadableStream` checks the option object’s keys. If it contains any key other than `onError`, it calls `console.warn('options are not supported yet, except onError')`. [src/jsx/dom/server.ts:54-56](src/jsx/dom/server.ts#L54-L56) The function forwards only `options.onError` to the underlying streaming renderer. [src/jsx/dom/server.ts:62](src/jsx/dom/server.ts#L62)

Consequently, the source does not show runtime handling for `identifierPrefix`, `namespaceURI`, `nonce`, `bootstrapScriptContent`, `bootstrapScripts`, `bootstrapModules`, `progressiveChunkSize`, or `signal`; their presence triggers the warning above. [src/jsx/dom/server.ts:32-42](src/jsx/dom/server.ts#L32-L42) [src/jsx/dom/server.ts:54-56](src/jsx/dom/server.ts#L54-L56) [src/jsx/dom/server.ts:62](src/jsx/dom/server.ts#L62)

`onError` is used by the underlying renderer for errors during stream startup and for rejected deferred callbacks. If absent, that renderer defaults it to `console.trace`. [src/jsx/streaming.ts:146-149](src/jsx/streaming.ts#L146-L149) Rejected deferred callbacks are logged with `console.log`, passed to `onError`, and replaced with an empty string for subsequent processing. [src/jsx/streaming.ts:171-195](src/jsx/streaming.ts#L171-L195) Errors caught while starting the stream are passed to `onError`; after the `try`/`catch`, the stream is closed unless it was cancelled. [src/jsx/streaming.ts:152-167](src/jsx/streaming.ts#L152-L167) [src/jsx/streaming.ts:203-217](src/jsx/streaming.ts#L203-L217)