server.ts

// API Routes
app.ws('/api/posts', (ws) => {
  // Send all the posts we have initially
  postsManager.getPaidPosts().forEach(post => {
    ws.send(JSON.stringify({
      type: 'post',
      data: post,
    }));
  });

  // Send each new post as it's paid for. If we error out, just close
  // the connection and stop listening.
  const postListener = (post: any) => {
    ws.send(JSON.stringify({
      type: 'post',
      data: post,
    }));
  };
  postsManager.addListener('post', postListener);

  // Keep-alive by pinging every 10s
  const pingInterval = setInterval(() => {
    ws.send(JSON.stringify({ type: 'ping' }));
  }, 10000);

  // Stop listening if they close the connection
  ws.addEventListener('close', () => {
    postsManager.removeListener('post', postListener);
    clearInterval(pingInterval);
  });
});