NodeJS Introduction to NodeJS Syllabus

For what type of workload is Node.js NOT well suited?

CPU-intensive (CPU-bound) tasks, because heavy computation blocks the single main thread and stalls the event loop, delaying all other requests.

What module system did Node.js traditionally use, and what modern standard does it now support?

Traditionally CommonJS (using require() and module.exports); it now also supports ECMAScript Modules (ESM) using import and export.

In CommonJS (Node.js), what is used to import and export modules?

require() is used to import a module, and module.exports (or exports) is used to export values from a module.

What does 'cross-platform' mean in the context of Node.js?

Node.js runs on multiple operating systems, including Windows, macOS, and Linux, allowing the same code to run across different platforms.

What does it mean that Node.js applications 'never buffer' data?

Node.js outputs data in chunks (streams) rather than buffering the entire response, so applications can process and emit data piece by piece, reducing memory use and latency.

Where can you download the official Node.js installer?

From the official website, nodejs.org, which provides installers and binaries for Windows, macOS, and Linux.

Which Node.js version is recommended for most users installing Node.js?

The LTS (Long-Term Support) version, because it is stable and supported for production use.

What tool is automatically installed alongside Node.js?

npm (Node Package Manager) is bundled with and installed automatically alongside Node.js.

How can you install Node.js on macOS using a package manager?

Using Homebrew with the command $\texttt{brew install node}$ (or install nvm first, then use nvm to install Node).

What is a common way to install Node.js on Linux distributions like Ubuntu?

Using the system package manager (e.g., $\texttt{sudo apt install nodejs npm}$), the NodeSource repository, or nvm for version management.

What is nvm?

nvm (Node Version Manager) is a command-line tool that lets you install, manage, and switch between multiple versions of Node.js on the same machine.

Why would a developer use nvm instead of a single system-wide Node install?

To easily install and switch between multiple Node.js versions per project, test code against different versions, and avoid permission issues and conflicts from a global install.

Which command installs a specific version of Node.js using nvm?

$\texttt{nvm install <version>}$, for example $\texttt{nvm install 20}$ or $\texttt{nvm install 20.11.0}$.

Which command installs the latest LTS version of Node.js with nvm?

$\texttt{nvm install --lts}$.

How do you switch to (activate) an installed Node.js version using nvm?

$\texttt{nvm use <version>}$, for example $\texttt{nvm use 20}$.

Which nvm command lists all Node.js versions installed on your machine?

$\texttt{nvm ls}$ (or $\texttt{nvm list}$).

Which nvm command lists all Node.js versions available to install?

$\texttt{nvm ls-remote}$ (on Windows nvm-windows: $\texttt{nvm list available}$).

How do you set a default Node.js version for new terminal sessions with nvm?

$\texttt{nvm alias default <version>}$, for example $\texttt{nvm alias default 20}$.

What is the difference between nvm on macOS/Linux and nvm-windows?

The original nvm (nvm-sh) is a shell script for macOS/Linux; Windows uses a separate project, nvm-windows, which has similar but not identical commands and is installed differently.

What file can define the Node.js version a project should use with nvm?

An $\texttt{.nvmrc}$ file placed in the project root; running $\texttt{nvm use}$ then reads it and switches to the specified version.

Which command verifies the installed Node.js version?

$\texttt{node -v}$ (or $\texttt{node --version}$), which prints the installed Node.js version, e.g. v20.11.0.

Which command verifies the installed npm version?

$\texttt{npm -v}$ (or $\texttt{npm --version}$).

What does the 'v' prefix in Node's version output (e.g., v20.11.0) indicate?

It simply stands for 'version'; the number that follows (20.11.0) is the semantic version of Node.js that is installed.

How can you verify Node.js works by running a quick command from the terminal?

Run $\texttt{node -e "console.log('Hello, Node!')"}$, or start the REPL with $\texttt{node}$ and type a JavaScript expression to see it evaluated.

What is the Node.js REPL and how do you start it?

The REPL (Read-Eval-Print Loop) is an interactive shell for running JavaScript line by line; you start it by typing $\texttt{node}$ (with no arguments) in the terminal.

What does the versioning scheme MAJOR.MINOR.PATCH mean in Node.js (semantic versioning)?

MAJOR changes introduce breaking changes, MINOR adds backward-compatible features, and PATCH provides backward-compatible bug fixes. So in $20.11.0$: MAJOR $=20$, MINOR $=11$, PATCH $=0$.

Compare Node.js and JavaScript in the browser: what is the key difference?

Browser JavaScript runs in a sandbox with access to the DOM and browser APIs but not the file system; Node.js runs on the server with access to the file system, network, OS, and modules, but has no DOM.

How does Node.js differ from traditional server technologies like PHP/Apache in handling requests?

Traditional servers often use a blocking, thread-per-request model, whereas Node.js uses a single-threaded, non-blocking, event-driven model that handles many concurrent connections with one thread.

Which command upgrades npm itself to the latest version?

$\texttt{npm install -g npm@latest}$ (installs the newest npm globally).

Name two categories of applications Node.js is especially well suited for.

Real-time applications (e.g., chat apps, live collaboration) and I/O-bound applications such as REST APIs, streaming services, and microservices. (Also single-page app backends and command-line tools.)