What is Node.js?

What Node.js is

Node.js is an open source runtime that runs JavaScript outside the browser, mostly on servers. Using the same language on the frontend and backend speeds up development and makes code easier to share.

Ryan Dahl created Node.js and showed it to the public in 2009. He wanted a way to build web servers that could handle many connections at once without waiting on slow tasks such as reading files or calling a database. He built it on V8, the JavaScript engine that Google made for the Chrome browser.

The npm package manager arrived in 2010 and made it easy to share and install code. In 2014 part of the community split off into a project called io.js, and the two projects joined again in 2015 under the Node.js Foundation. Since 2019 Node.js has been hosted by the OpenJS Foundation, and new major versions come out on a regular schedule with long term support releases for production use.

How Node.js works

A web browser has a JavaScript engine inside it. Node.js takes that same kind of engine, V8, and puts it in a program you can run on a server or on your own computer. It then adds features a browser does not give you, such as reading and writing files, opening network connections and starting other programs.

Node.js runs your code on a single main thread using an event loop. When your code asks for something slow, such as a database query, Node.js does not stop and wait. It hands the task off, keeps working on other requests, and runs your callback, promise or async function when the result is ready. This style is called non-blocking I/O.

Code is split into modules, and a file named package.json lists the packages a project depends on. You install packages from the npm registry with the npm command. Frameworks such as Express, Fastify and NestJS sit on top of Node.js to make building an HTTP server or REST API quicker.

Key features of Node.js

• Event loop

  One main thread handles many connections by never waiting on slow work. This suits APIs, chat and other apps that mostly move data around.

• npm package registry

  npm ships with Node.js and gives access to a very large collection of open source packages. Most common tasks already have a library.

• One language everywhere

  The same JavaScript or TypeScript can be used in the browser and on the server. Teams can share code, types and skills between both sides.

• Built-in modules

  Node.js includes modules for files, HTTP, streams, cryptography and more. A simple web server needs no extra packages.

• Long term support

  Selected major versions are marked LTS and receive fixes for an extended period. This gives companies a stable version to run in production.

• Cross-platform

  The same project runs on Windows, macOS and Linux. It also runs well inside Docker containers and on most cloud hosts.

When to use Node.js

Node.js compared with alternatives

How to start learning Node.js

1. 01Learn the basics of JavaScript first, including functions, objects, promises and async and await.
2. 02Download the LTS installer from nodejs.org, then run node --version in a terminal to check it works.
3. 03Follow the introduction guides in the official Node.js documentation and write a small script that reads a file.
4. 04Create a project with npm init, install a package with npm install, and learn what package.json does.
5. 05Build a first project such as a small REST API with Express or a simple Discord bot.

What Node.js costs

Node.js is free and open source under the MIT license, including for commercial use. npm is free for public packages. You only pay for the servers or hosting that run your app.

How DATAL Projects uses Node.js

Node.js is part of our backend development work in the Philippines. Common uses:

• APIs and backend services
• Discord bots
• Build tools and automation scripts

Common questions about Node.js