Minimal Node.js server with JSON support

server.js

/**
 * Minimal Node.js server with JSON support.
 * 
 * Usage:  node server.js
 * Client: curl -i -d '{}' 127.0.0.1:8000
 * 
 * NOTES:
 *  - `Request` and `Response` classes can be extended. For instance, you can 
 *    extend `Request` to override `json` function in order to  raise a   
 *    specific custom error on parsing failure. You'll need then to reconfigure 
 *    the `IncomingMessage` argument of the `createServer` function.
 */

import {
	Buffer
} from 'node:buffer';
import {
	createServer,
	IncomingMessage,
	ServerResponse
} from 'node:http';

class Request extends IncomingMessage {
	json () {
		return new Promise((resolve, reject) => {
			const data = [];
			this.on('data', (chunk) => data.push(chunk));
			this.on('error', (e) => reject(e));
			this.on('end', () => {
				try {
					resolve(JSON.parse(Buffer.concat(data)));
				} catch (e) {
					reject(e);
				}
			});
		});
	}
}

class Response extends ServerResponse {
	json (code, data) {
		this.writeHead(code, { 'Content-Type': 'application/json' });
		this.end(JSON.stringify(data));
	}
}

createServer({
	IncomingMessage: Request,
	ServerResponse: Response
}, async (req, res) => {
	// Circular references.
	req.res = res;
	res.req = req;
	// Handle request.
	try {
		console.log('Reading body...');
		const data = await req.json();
		console.log(`Body: ${JSON.stringify(data)}`);
		res.json(200, { message: 'ok' });
	} catch (e) {
		res.json(400, { error: e.message });
	};
}).listen(8000, '0.0.0.0', () => {
	console.log('listening...');
});

Raise a specific error on JSON parsing failure:

class HTTPError extends Error {
	constructor (code, ...args) {
		super(...args);
		this.code = code;
	}
}

class CustomRequest extends Request {
	async json () {
		try {
			return await super.json();
		} catch (e) {
			throw new HTTPError(415, 'Invalid payload');
		}
	}
}

createServer({
	IncomingMessage: CustomRequest,
	ServerResponse: Response
}, async (req, res) => {
	try {
		const data = await req.json();
	} catch (e) {
		if (e instanceof HTTPError) {
			res.json(e.code, { error: e.message });
		}
	}
}).listen(8000);