JelenJS SSR

Server-Side Rendering package for JelenJS framework. Enables rendering JelenJS components to HTML strings on the server for improved SEO and initial page load performance.

Features

• 🚀 Server-Side Rendering - Render JelenJS components to HTML strings
• 🔄 Hydration Support - Seamless client-side hydration
• 🎯 DOM Shim - Complete DOM API emulation for Node.js
• 📦 Zero Dependencies - Lightweight and self-contained
• 🛠️ TypeScript Support - Full type safety

Installation

npm install jelenjs-ssr

Quick Start

Basic SSR

import { renderToString } from 'jelenjs-ssr';
import { signal } from 'jelenjs';

// Define a simple component
function Counter({ initialCount = 0 }) {
  const [count, setCount] = signal(initialCount);
  
  return (
    <div>
      <h1>Count: {count}</h1>
      <button onClick={() => setCount(count() + 1)}>
        Increment
      </button>
    </div>
  );
}

// Render to HTML string
const html = await renderToString(Counter, { initialCount: 5 });
console.log(html);
// Output: <div><h1>Count: 5</h1><button>Increment</button></div>

Complete HTML Document

import { renderToDocument } from 'jelenjs-ssr';

const document = await renderToDocument(Counter, { initialCount: 0 }, {
  title: 'My JelenJS App',
  meta: [
    { name: 'description', content: 'A counter app built with JelenJS' }
  ],
  scripts: ['/assets/main.js']
});

console.log(document);
// Output: Complete HTML document with head, body, and hydration data

With Hydration Data

import { renderToStringWithData } from 'jelenjs-ssr';

const result = await renderToStringWithData(Counter, { initialCount: 10 }, {
  includeHydrationData: true,
  prettyPrint: true
});

console.log(result.html);           // Rendered HTML
console.log(result.hydrationData);  // Data for client-side hydration

API Reference

renderToString(component, props?, options?)

Renders a component to an HTML string.

Parameters:

• component - JelenJS component function
• props - Props to pass to the component
• options - Rendering options

Returns: Promise<string>

renderToStringWithData(component, props?, options?)

Renders a component with hydration data.

Returns: Promise<SSRRenderResult>

interface SSRRenderResult {
  html: string;
  hydrationData?: HydrationData;
  styles?: string[];
  meta?: MetaTag[];
}

renderToDocument(component, props?, documentOptions?, renderOptions?)

Renders a component to a complete HTML document.

Returns: Promise<string>

createHTMLDocument(content, options?)

Creates a complete HTML document from rendered content.

DOM Shim

The package includes a complete DOM shim for Node.js:

import { setupSSRGlobals, document, window } from 'jelenjs-ssr/dom-shim';

// Setup global DOM objects
setupSSRGlobals();

// Now you can use document and window in Node.js
const element = document.createElement('div');
element.textContent = 'Hello, SSR!';
console.log(element.toString()); // <div>Hello, SSR!</div>

Integration Examples

Express.js

import express from 'express';
import { renderToDocument } from 'jelenjs-ssr';
import App from './App';

const app = express();

app.get('*', async (req, res) => {
  try {
    const html = await renderToDocument(App, { url: req.url }, {
      title: 'My App',
      scripts: ['/client.js']
    });
    
    res.send(html);
  } catch (error) {
    res.status(500).send('Server Error');
  }
});

app.listen(3000);

Next.js Style API

// pages/blog/[slug].tsx
export default function BlogPost({ post }) {
  return (
    <article>
      <h1>{post.title}</h1>
      <div>{post.content}</div>
    </article>
  );
}

export async function getStaticProps({ params }) {
  const post = await fetchPost(params.slug);
  return { props: { post } };
}

export async function getStaticPaths() {
  const posts = await fetchAllPosts();
  return {
    paths: posts.map(post => ({ params: { slug: post.slug } })),
    fallback: false
  };
}

Performance Tips

1. Use Static Analysis - Pre-analyze components to identify static vs dynamic parts
2. Cache Rendered Content - Cache HTML output for static content
3. Selective Hydration - Only hydrate interactive components
4. Stream Rendering - Use streaming for large pages (coming soon)

Limitations

• Effects in SSR - Effects don't run during SSR (by design)
• Browser APIs - Browser-specific APIs need polyfills or conditional usage
• Async Components - Async components require special handling

Roadmap

• [ ] Streaming SSR support
• [ ] Automatic static/dynamic component detection
• [ ] Built-in caching strategies
• [ ] Performance profiling tools
• [ ] Integration with popular frameworks

License

MIT