Node.js

 

• Node.js is an event-driven non-blocking JavaScript middleware. Opponents are Spring, Django, Java Enterprise Edition (Java EE)… or Deno, Bun (written in Zig)… in the JavaScript/TypeScript ecosystem.
• Version:node -v
• Capability: node -h
• Execution: node Main.js
• Node.js comes with a lot of native libraries like fs (file system), http, path…, but its ecosystem is rich of numerous external libraries whose consistent management relies on npm (Node.js package manager)
• Program example (using Puppeteer ext. lib.) here…

npm is in sync with a package.json file for configuration purposes including file location, nature, purpose… library versioning, licensing, etc.

Library versioning

• Reminder on versioning: "4.17.1" ⤳ major: 4 (backward incompatible), minor: 17 (backward compatible), and patch: 1
• So "express": "~4.17.1", ⤳ patches only, e.g., up to "4.17.3"
• So "express": "^4.17.1", ⤳ up to non-breaking API, i.e., very latest minor version, e.g., up to "4.18.1"
• "mongodb": "*", ⤳ upgrades to very last version

Other configurations

• "engines": { "node": ">=10" }, ⤳ fixes compatible Node.js version
• "scripts": { "start": "node js/Main.js" },
• Etc.

• Where is Node.js on macOS ⤳ which node ⤳ /usr/local/bin/node
• Where is Node.js on Windows ⤳ Get-Command node ⤳ C:\Program Files\nodejs\node.exe
• Update of Node.js ⤳ best and simpler solution is downloading the latest version and installing it…
  • macOS (update Homebrew) ⤳ brew -v;brew upgrade
  • macOS ⤳ brew uninstall --force node (if installed with Homebrew only)
  • -OR- macOS (install Node Version Manager) ⤳ brew install nvm/brew reinstall nvm
  • macOS ⤳ nvm uninstall v17.8

• Version check of npm: npm -v
• Where is npm on macOS: which npm ⤳ /usr/local/bin/npm
• Where is npm on Windows: Get-Command npm ⤳ C:\Program Files\nodejs\npm.cmd
• Update: <sudo> npm install npm@latest -g (-g means “global”)
• Where are installed modules? npm root -g
• What are global installed modules? npm list -g -depth=0
• Installation of library from a directory having a package.json file, example: <sudo> npm install ./lib/tracking.js-master

• Programming Node.js with TypeScript here…
• Blocking versus non-blocking here…
• Node.js module system here…
• Environment variables within Node.js
• Programming Web server with Node.js here…
• Querying the Web with Node.js here…
• Database tiers with Node.js ⤳ SQL here…
• Database tiers with Node.js ⤳ NoSQL here…
• Micro-services with Node.js here…
• Messaging with Node.js here…
• Authentification here…
• Orchestration here… TO DO
• Web streams here… TO DO
• WebAssembly here…

• Internet of Things -IoT-: Node-RED