Mainstream npm Framework Compatibility (Hono, Express, LangChain)

1. Overview

Amber is designed not just for scripts, but as a drop-in execution platform for mainstream TypeScript and JavaScript frameworks.

In Amber v1.5.0, we completed end-to-end verification and API hardening for three ecosystem pillars:

1. Hono: The ultra-fast, lightweight web framework built on Web Standards.
2. Express: The industry standard Node.js server framework.
3. LangChain: The leading LLM application and agent orchestration framework.

2. Hono Framework on Amber

Hono relies heavily on standard Web APIs (Request, Response, Headers, fetch) and Node's AsyncLocalStorage for request context storage.

Key Capabilities Enabled in v1.5.0

• Response.json(data, init): Native static factory producing JSON responses with proper headers.
• Response.redirect(url, status): Standard redirect support.
• Headers.prototype.getSetCookie(): Standard cookie extraction array.
• AsyncLocalStorage Context Storage: Guaranteed context propagation across async/await promise boundaries in hono/context-storage.

Example: Running Hono API

import { Hono } from 'hono';
import { AsyncLocalStorage } from 'node:async_hooks';

const app = new Hono();
const als = new AsyncLocalStorage();

// Context middleware
app.use('*', async (c, next) => {
  return als.run({ traceId: 'amber-req-999' }, async () => {
    await next();
  });
});

app.get('/api/health', (c) => {
  const store = als.getStore();
  return c.json({ status: 'healthy', traceId: store?.traceId });
});

export default app;

3. Express Framework on Amber

Express applications require full fidelity on http.IncomingMessage, http.ServerResponse, and Node stream pipelines.

Key Capabilities Enabled in v1.5.0

• res.status(code).json(body): Fluent response methods.
• res.set(), res.header(), res.get(): Express header shortcuts.
• req.socket & req.headers: Full network connection and header metadata.
• stream/promises (pipeline, finished): Promise-based stream piping.
• timers/promises (setTimeout, setImmediate): Modern async sleep and scheduling.

Example: Express Microservice

import http from 'node:http';
import { pipeline } from 'node:stream/promises';
import { setTimeout } from 'node:timers/promises';

const server = http.createServer(async (req, res) => {
  if (req.method === 'POST' && req.url === '/process') {
    // Simulate async pipeline work
    await setTimeout(20);
    return res.status(200).json({ processed: true, client: req.socket?.remoteAddress });
  }

  res.status(404).send('Not Found');
});

server.listen(3000, () => {
  console.log('Server listening on port 3000');
});

4. LangChain on Amber

LangChain and LLM orchestrators make heavy use of Web Streams, SSE streaming, and async context tracking.

Key Capabilities Enabled in v1.5.0

• ReadableStream.from(iterable): Creates readable streams directly from token arrays, generators, or async generators.
• for await (const chunk of stream): Async iterator support on all ReadableStream instances.
• TransformStream Piping: Full pipeline streaming via stream.pipeThrough(transformer).
• AbortSignal.timeout(ms) & AbortSignal.any(): Automatic LLM call timeout and combined cancellation.

Example: LLM Token Streaming Pipeline

// Token stream from Amber Edge SLM or external provider
const tokenStream = ReadableStream.from([
  'Thinking', ' ', 'step', ' ', 'by', ' ', 'step', '...'
]);

// Transform stream to format SSE chunks
const sseTransform = new TransformStream({
  transform(token, controller) {
    controller.enqueue(`data: ${JSON.stringify({ token })}\n\n`);
  }
});

const outputStream = tokenStream.pipeThrough(sseTransform);

// Asynchronously consume streaming tokens
for await (const sseChunk of outputStream) {
  process.stdout.write(sseChunk);
}