JavaScript
May 5, 2025 · View on GitHub
It's nothing to do with Java.
NodeJS
NodeJS or Node.js is a server-side JavaScript engine built on Google Chrome's V8 JavaScript engine that can be used for both frontend and backend development.
Uses a non-blocking, event-driven architecture, making it ideal for building scalable and high-performance applications that handle a large number of simultaneous connections.
NodeJS operates on a single-threaded event loop model, but it uses non-blocking asynchronous I/O operations to handle concurrency efficiently
Like Python, NodeJS has a vast ecosystem of libraries, which you can search at npmjs.com.
NodeJS is used for everything from web development, to APIs and microservices, to CLI tools (although there are better languages for CLI like Golang, Python, Perl and Bash).
NPM
NodeJS Package Manager.
Install it using your system package manager and then use it to install your NodeJS libraries.
brew install npm
On any Mac or Linux, from DevOps-Bash-tools:
install_packages.sh npm
NPM install package:
npm install "$package"
Remember to commit the resulting package.json and package-lock.json files to Git.
Both files as in JSON format.
package.json- lists packages you've installed directlypackage-lock.json- lists the exact versions of all package dependencies so you can reproduce without annoying library version change related issues
Install all packages of the exact versions from ``packages-lock.json`:
npm install
NVM - Node Version Manager
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.2/install.sh | bash
Clones to ~/.nvm.
Reload shell to pick up the addition to .bashrc.
Show current node version:
nvm ls
-> system
iojs -> N/A (default)
node -> stable (-> N/A) (default)
unstable -> N/A (default)
List available versions:
nvm ls-remote
Install latest version of NodeJS:
nvm install node
Install specific version:
nvm install v23.11.0
nvm use node
node --version
v23.11.0
nvm ls
-> v23.11.0
system
default -> node (-> v23.11.0)
iojs -> N/A (default)
unstable -> N/A (default)
node -> stable (-> v23.11.0) (default)
stable -> 23.11 (-> v23.11.0) (default)
...
REPL
To start an interactive Javascript shell, just type:
node
Then behold this horror:
> "11" + 1
'111'
> "11" - 1
10
Which brings us on to... strict variable typing...
TypeScript
Type safe superset of JavaScript with optional static type checking.
Transpiles (converts) to JavaScript eg. src/*.ts => dist/index.js.
Not compiles since it doesn't translate to binary or byte code.
Example variable type enforcement, just suffix the : <type> to a variable:
let name: string = "Hari";
name = 1; // type error
Install TypeScript
npm install -g typescript
Convert TypeScript to JavaScript
tsc example.ts
Generates example.js.
Run it:
node example.js
TypeScript Config
Create a tsconfig.json for project settings:
tsc --init
TypeScript REPL
tsx
npm install -g tsx
tsx
Welcome to Node.js v23.7.0.
Type ".help" for more information.
> 1 + 1
2
>
ts-node
npm install -g ts-node
Start the REPL:
ts-node
List the packages:
npm ls -g ts-node typescript
/opt/homebrew/lib
└─┬ ts-node@10.9.2
└── typescript@5.8.3
If you get an issue with REPL commands resulting in ... line continuation instead of returning the result.
ts-node
> 1 + 1
...
... ;
... ;
...
Use tsx instead.
Libraries
- :octocat: cure53/DOMPurify - sanitize HTML to avoid XSS attacks. You can see this used in my TamperMonkey script jira_description_autofill.js.
- :octocat: https://github.com/highlightjs/highlight.js - syntax highlighter
Repos
Memes
JavaScript - The Good Parts
JavaScript TypeScript Friends
Men Who Take Risks
Imported Package Tariffs
Why Are You Crying Son
