Category · Node.js

JavaScript outside the browser

What Node.js and the event loop are, modules and npm, asynchrony, files, events, process and the environment, an HTTP server without a framework, streams, errors, and tests. The foundation for Express and any JS backend.

10 lessons101 min

To the first lesson Cheatsheet now

Topics, each as its own lesson

01The runtime and the event loopDemo

One thread, a task queue, and no stopping to wait.

02Modules and npm

import/export split code into files, npm brings in other people's.

03async/await and Promise.all

Wait without blocking. Independent requests run in parallel.

04Files and paths

fs reads and writes, path joins paths without OS surprises.

05Events and process errors

EventEmitter: someone shouts, someone listens. And what to do when it all falls over.

06process: environment, arguments, exit code

How a program learns where it's running and with which parameters.

07An HTTP server without a framework

Express is just a wrapper. Underneath is the node:http module.

08Streams and pipeline

You don't need to read a 2 GB file into memory whole. Process it in chunks.

09Errors: throw, try/catch, cause

An error isn't the end of the world if you know where to catch it.

10Tests: node:test and assert

A test runner is already built into Node. No packages needed.

0/10 topics open. This is the course intro, not the whole course on one page.

In the knowledge base

Reference pages for the technologies on this topic: who maintains them, when to use them and what interviews ask.