# preact-render-to-string
**Repository Path**: mirrors_developit/preact-render-to-string
## Basic Information
- **Project Name**: preact-render-to-string
- **Description**: 📄 Universal rendering for Preact: render JSX and Preact components to HTML.
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-06-17
- **Last Updated**: 2026-05-16
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
# preact-render-to-string
[](https://www.npmjs.com/package/preact-render-to-string)
[](https://github.com/preactjs/preact-render-to-string/actions/workflows/ci.yml)
Render JSX and [Preact](https://github.com/preactjs/preact) components to an HTML string.
Works in Node & the browser, making it useful for universal/isomorphic rendering.
\>\> **[Cute Fox-Related Demo](http://codepen.io/developit/pen/dYZqjE?editors=001)** _(@ CodePen)_ <<
---
### Render JSX/VDOM to HTML
```js
import { render } from 'preact-render-to-string';
import { h } from 'preact';
/** @jsx h */
let vdom =
content
;
let html = render(vdom);
console.log(html);
//
content
```
### Render Preact Components to HTML
```js
import { render } from 'preact-render-to-string';
import { h, Component } from 'preact';
/** @jsx h */
// Classical components work
class Fox extends Component {
render({ name }) {
return {name};
}
}
// ... and so do pure functional components:
const Box = ({ type, children }) => (
{children}
);
let html = render(
);
console.log(html);
//
Finn
```
---
### Render JSX / Preact / Whatever via Express!
```js
import express from 'express';
import { h } from 'preact';
import { render } from 'preact-render-to-string';
/** @jsx h */
// silly example component:
const Fox = ({ name }) => (
{name}
This page is all about {name}.
);
// basic HTTP server via express:
const app = express();
app.listen(8080);
// on each request, render and return a component:
app.get('/:fox', (req, res) => {
let html = render();
// send it back wrapped up as an HTML5 document:
res.send(`${html}`);
});
```
### Error Boundaries
Rendering errors can be caught by Preact via `getDerivedStateFromErrors` or `componentDidCatch`. To enable that feature in `preact-render-to-string` set `errorBoundaries = true`
```js
import { options } from 'preact';
// Enable error boundaries in `preact-render-to-string`
options.errorBoundaries = true;
```
---
### `Suspense` & `lazy` components with [`preact/compat`](https://www.npmjs.com/package/preact)
```bash
npm install preact preact-render-to-string
```
```jsx
export default () => {
return
Home page
;
};
```
```jsx
import { Suspense, lazy } from 'preact/compat';
// Creation of the lazy component
const HomePage = lazy(() => import('./pages/home'));
const Main = () => {
return (
Loading}>
);
};
```
```jsx
import { renderToStringAsync } from 'preact-render-to-string';
import { Main } from './main';
const main = async () => {
// Rendering of lazy components
const html = await renderToStringAsync();
console.log(html);
//
Home page
};
// Execution & error handling
main().catch((error) => {
console.error(error);
});
```
---
### Streaming
> [!NOTE]
> This is an early version of our streaming implementation.
Preact supports streaming HTML to the client incrementally, flushing `` fallbacks immediately and replacing them with the resolved content as data arrives. This reduces Time to First Byte and allows the browser to start parsing earlier.
#### `renderToReadableStream` — Web Streams
```jsx
import { renderToReadableStream } from 'preact-render-to-string/stream';
import { Suspense, lazy } from 'preact/compat';
const Profile = lazy(() => import('./Profile'));
const App = () => (
My AppLoading profile…}>
);
// Works in any Web Streams environment (Deno, Bun, Cloudflare Workers, …)
export default {
fetch() {
const stream = renderToReadableStream();
// stream.allReady resolves once all suspended content has been flushed
return new Response(stream, {
headers: { 'Content-Type': 'text/html' }
});
}
};
```
The returned `ReadableStream` has an extra `allReady: Promise` property that resolves once every suspended subtree has been written. Await it before sending the response if you need the complete document before anything is flushed (e.g. for static export). At which point you might be better off using `renderToStringAsync` though.
```js
const stream = renderToReadableStream();
await stream.allReady; // wait for full render
```
#### `renderToPipeableStream` — Node.js Streams
```jsx
import { createServer } from 'node:http';
import { renderToPipeableStream } from 'preact-render-to-string/stream-node';
import { Suspense, lazy } from 'preact/compat';
const Profile = lazy(() => import('./Profile'));
const App = () => (
My AppLoading profile…}>
);
createServer((req, res) => {
res.setHeader('Content-Type', 'text/html');
const { pipe, abort } = renderToPipeableStream(, {
onShellReady() {
// Called once the synchronous shell is ready to stream.
pipe(res);
},
onAllReady() {
// Called once every suspended subtree has been flushed.
},
onError(error) {
console.error(error);
res.statusCode = 500;
}
});
// Optional: abort the render after a timeout
setTimeout(abort, 10_000);
}).listen(8080);
```
| Option | Description |
|---|---|
| `onShellReady()` | Called synchronously once the initial shell has been rendered and streaming is about to start. Pipe here for fastest TTFB. |
| `onAllReady()` | Called after all `` boundaries have resolved and the stream is complete. |
| `onError(error)` | Called for render errors inside suspended subtrees. |
Calling `abort()` stops the render and destroys the stream; any pending suspended subtrees are dropped.
---
### License
[MIT](http://choosealicense.com/licenses/mit/)