Worker Threads in Node.js 18

server.js

const http = require('http');
const { Worker } = require('worker_threads');

const slowApiEndpoint = 'https://api.example.com/slow-endpoint';

http.createServer((req, res) => {
  if (req.url === '/api-data') {
    const worker = new Worker('./slow-api-worker.js');
    worker.on('message', (data) => {
      res.writeHead(200, { 'Content-Type': 'application/json' });
      res.write(data);
      res.end();
    });
    worker.on('error', (err) => {
      console.error(`Worker error: ${err}`);
      res.writeHead(500, { 'Content-Type': 'text/plain' });
      res.write('500 Internal Server Error');
      res.end();
    });
    worker.on('exit', (code) => {
      console.log(`Worker exited with code ${code}`);
    });
  } else {
    res.writeHead(404, { 'Content-Type': 'text/plain' });
    res.write('404 Not Found');
    res.end();
  }
}).listen(8080, () => {
  console.log('Server listening on port 8080');
});

slow-api-worker.js

const { Worker } = require('worker_threads');
const https = require('https');

const slowApiEndpoint = 'https://api.example.com/slow-endpoint';

function makeSlowApiCall() {
  return new Promise((resolve, reject) => {
    https.get(slowApiEndpoint, (res) => {
      let data = '';
      res.on('data', (chunk) => {
        data += chunk;
      });
      res.on('end', () => {
        resolve(data);
      });
    }).on('error', (err) => {
      reject(err);
    });
  });
}

function makeApiCallAndSendResponse() {
  makeSlowApiCall().then((data) => {
    worker.postMessage(data);
  }).catch((err) => {
    console.error(`API call error: ${err}`);
    worker.postMessage('500 Internal Server Error');
  });
}

const worker = new Worker(() => {
  makeApiCallAndSendResponse();
});

worker.on('error', (err) => {
  console.error(`Worker error: ${err}`);
});

worker.on('exit', (code) => {
  console.log(`Worker exited with code ${code}`);
});