preactjs
preact-render-to-string
Render JSX and Preact components to an HTML string.
Works in Node & the browser, making it useful for universal/isomorphic rendering.
>> Cute Fox-Related Demo (@ CodePen) <<
Render JSX/VDOM to HTML
import { render } from 'preact-render-to-string';
import { h } from 'preact';
/** @jsx h */
let vdom = <div class="foo">content</div>;
let html = render(vdom);
console.log(html);
// <div class="foo">content</div>Render Preact Components to HTML
import { render } from 'preact-render-to-string';
import { h, Component } from 'preact';
/** @jsx h */
// Classical components work
class Fox extends Component {
render({ name }) {
return <span class="fox">{name}</span>;
}
}
// ... and so do pure functional components:
const Box = ({ type, children }) => (
<div class={`box box-${type}`}>{children}</div>
);
let html = render(
<Box type="open">
<Fox name="Finn" />
</Box>
);
console.log(html);
// <div class="box box-open"><span class="fox">Finn</span></div>Render JSX / Preact / Whatever via Express!
import express from 'express';
import { h } from 'preact';
import { render } from 'preact-render-to-string';
/** @jsx h */
// silly example component:
const Fox = ({ name }) => (
<div class="fox">
<h5>{name}</h5>
<p>This page is all about {name}.</p>
</div>
);
// basic HTTP server via express:
const app = express();
app.listen(8080);
// on each request, render and return a component:
app.get('/:fox', (req, res) => {
let html = render(<Fox name={req.params.fox} />);
// send it back wrapped up as an HTML5 document:
res.send(`<!DOCTYPE html><html><body>${html}</body></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
import { options } from 'preact';
// Enable error boundaries in `preact-render-to-string`
options.errorBoundaries = true;Suspense & lazy components with preact/compat
npm install preact preact-render-to-stringexport default () => {
return <h1>Home page</h1>;
};import { Suspense, lazy } from 'preact/compat';
// Creation of the lazy component
const HomePage = lazy(() => import('./pages/home'));
const Main = () => {
return (
<Suspense fallback={<p>Loading</p>}>
<HomePage />
</Suspense>
);
};import { renderToStringAsync } from 'preact-render-to-string';
import { Main } from './main';
const main = async () => {
// Rendering of lazy components
const html = await renderToStringAsync(<Main />);
console.log(html);
// <h1>Home page</h1>
};
// Execution & error handling
main().catch((error) => {
console.error(error);
});