import ReactDOMServer from 'react-dom/server.browser'
export type RenderToStringOptions = {
/**
* Critical scripts that need to execute immediately (will use async).
* These are added to bootstrapModules and generate both modulepreload links and async script tags.
*/
preloads?: string[]
}
/**
* Buffered SSR - renders to full HTML string.
* Deferred preloads and server data are rendered in the React tree
* (React 19 hoists to ).
*/
export const renderToString = async (
app: React.ReactElement,
options: RenderToStringOptions
) => {
const readableStream = await ReactDOMServer.renderToReadableStream(app, {
bootstrapModules: options.preloads,
})
await readableStream.allReady
const reader = readableStream.getReader()
const decoder = new TextDecoder('utf-8')
let out = ''
while (true) {
const { done, value } = await reader.read()
if (done) break
out += decoder.decode(value, { stream: true })
}
out += decoder.decode()
return out
}
/**
* Streaming SSR - returns ReadableStream directly.
* Skips allReady wait for faster TTFB.
*/
export const renderToStream = async (
app: React.ReactElement,
options: RenderToStringOptions
): Promise => {
return ReactDOMServer.renderToReadableStream(app, {
bootstrapModules: options.preloads,
})
}