nodejs

name	nodejs
description	Node.js runtime patterns, streams, worker threads, clustering, event loop optimization, and production-grade server architecture
layer	domain
category	backend
triggers	["node.js","nodejs","express","worker threads","node streams","clustering","event loop","node performance"]
inputs	["Backend architecture requirements","Performance bottleneck descriptions","Scaling requirements"]
outputs	["Node.js implementation patterns","Performance optimization strategies","Production deployment configurations"]
linksTo	["websockets","message-queues","microservices","graphql","prisma","drizzle","redis"]
linkedFrom	["error-handling","logging","testing"]
preferredNextSkills	["prisma","redis","microservices","websockets"]
fallbackSkills	["python","golang"]
riskLevel	low
memoryReadPolicy	selective
memoryWritePolicy	none
sideEffects	[]

Node.js Domain Skill

Purpose

Provide expert-level guidance on Node.js runtime patterns, server architecture, performance optimization, and production deployment. This skill covers the entire Node.js ecosystem from event loop internals to clustering strategies.

Key Patterns

1. Event Loop Awareness

The event loop is single-threaded. Never block it.

// BAD: Blocking the event loop
const data = fs.readFileSync('/large-file.json');
const parsed = JSON.parse(data); // Blocks for large files

// GOOD: Non-blocking with streams
const stream = fs.createReadStream('/large-file.json');
const parsed = await pipeline(stream, new JSONParseStream());

Phases to understand:

• Timers: setTimeout, setInterval callbacks
• Pending callbacks: I/O callbacks deferred from previous cycle
• Poll: Retrieve new I/O events; execute I/O callbacks
• Check: setImmediate callbacks
• Close: socket.on('close') callbacks

Use setImmediate() to yield to the event loop during CPU-intensive synchronous work:

function processLargeArray(array, callback) {
  const CHUNK = 1000;
  let index = 0;

  function doChunk() {
     limit = .(index + , array.);
     (; index < limit; index++) {
      (array[index]);
    }
     (index < array.) {
      (doChunk); 
    }  {
      ();
    }
  }
  ();
}