Every article tagged Node.js, in one place.
Showing 21 articles
If you learned Node.js a few years ago, you probably install packages for things the runtime now does itself. Here's a tour of built-ins in current LTS versions. fetch, WebSocket and Web APIs const res = await fetch('https://api.github.com/repos/nodejs/node');...
Long answers can take many seconds to generate. Streaming shows text as it is produced, so users see progress immediately instead of staring at a spinner. Streaming on the server The SDK's messages.stream() helper gives you an async iterator of events plus a t...
In this tutorial you'll build an MCP server that exposes a get_github_repo tool, and run it over stdio so desktop AI apps can launch it. 1. Set up the project mkdir github-mcp && cd github-mcp npm init -y npm install @modelcontextprotocol/sdk zod npm install -...
Node.js ships a full test runner. For many backends and libraries it replaces Jest or Mocha entirely, with zero dependencies. Writing tests // test/cart.test.js import { describe, it, beforeEach } from 'node:test'; import assert from 'node:assert/strict'; impo...
A Dockerfile that "works" and one that's good for production differ in image size, build speed, security and how the app shuts down. Here's a solid template. # syntax=docker/dockerfile:1 # ---------- dependencies (all, for building) ---------- FROM node:22-alp...
OpenTelemetry's auto-instrumentation patches popular libraries (http, Express, pg, Redis, fetch and many more) so you get traces with almost no code changes. Zero-code setup npm install @opentelemetry/api @opentelemetry/auto-instrumentations-node export OTEL_S...
Node.js supports two module systems: the original CommonJS ( require ) and standard ES modules ( import ). New projects should use ESM, but you'll meet both. Turning on ESM // package.json { "type": "module" } With "type": "module" , .js files are ESM. Without...
Configuration such as database URLs and API keys belongs in environment variables, not in code. Node.js can now load .env files itself. Loading from the command line # .env DATABASE_URL=postgres://localhost:5432/app PORT=3000 node --env-file=.env src/server.js...
console.log("user " + id + " failed") is fine on a laptop. In production you need logs that machines can search and filter: JSON with consistent fields, levels and request IDs. Basic setup import pino from 'pino'; export const logger = pino({ level: process.en...
Reading a 5 GB log file with fs.readFile loads all 5 GB into memory. Streams process data in small chunks, so memory use stays flat no matter how big the input is. The four stream types Readable - a source (file, HTTP request, database cursor). Writable - a de...
MongoDB itself is flexible about document shape. Mongoose adds schemas, validation, defaults and helpers on top of the official driver, which brings structure to application code. Defining a model import mongoose from 'mongoose'; await mongoose.connect(process...
Stdio servers run on the user's machine. A remote MCP server runs on your infrastructure and is reached over HTTP, which is how SaaS products expose their tools to AI apps. The current HTTP transport is Streamable HTTP : one endpoint that accepts JSON-RPC over...
Node.js runs your JavaScript on a single thread. That's fine for I/O, but a CPU-heavy task (resizing images, parsing a huge file, heavy maths) blocks the event loop, and every other request waits. Spot the problem app.get('/report', (req, res) => { const resul...
For years, running TypeScript in Node.js meant a compile step or a loader like ts-node or tsx. Recent Node.js versions can run .ts files directly by stripping the type annotations. Try it // greet.ts interface Person { name: string } function greet(p: Person):...
Express 5 finally handles async route handlers properly: if an async handler throws or returns a rejected promise, the error goes to your error middleware. No more express-async-errors or wrapping every route in try/catch. Async handlers just work app.get('/us...
A GraphQL server needs two things: a schema describing types and operations, and resolvers that fetch the data for each field. Setup npm install @apollo/server graphql Schema and resolvers // server.js import { ApolloServer } from '@apollo/server'; import { st...
Most API breaches come from a few well-known mistakes. Work through this checklist for every Node.js service you deploy. 1. Validate every input import { z } from 'zod'; const CreateOrder = z.object({ productId: z.uuid(), quantity: z.number().int().min(1).max(...
Fetch 50 books with their authors, and a naive server runs 1 query for the books plus 50 queries for authors. That's the N+1 problem , and it's the most common GraphQL performance issue. Why it happens Book: { // called once per book, each with its own query a...
Containers and process managers stop your app by sending SIGTERM . If you exit immediately, requests in progress fail and database transactions are cut off. A graceful shutdown finishes the current work first. The steps Stop accepting new connections. Let in-f...
The default in-memory session store loses every session on restart and doesn't work with more than one server. Redis is the standard fix: fast, shared and with built-in expiry. Setup npm install express-session connect-redis redis import express from 'express'...
A memory leak shows up as memory that keeps climbing until the process is killed or restarts. The fix starts with proving where the memory goes. 1. Confirm the leak setInterval(() => { const { heapUsed, rss } = process.memoryUsage(); console.log(`heap ${(heapU...
