Tooling

JavaScript’s tooling is decentralised; most teams assemble their own stack from npm packages.

Runtimes

• Node.js, the dominant server-side runtime.

• Deno, secure-by-default, TypeScript-native.

• Bun, fast all-in-one runtime + bundler + package manager.

• Browsers (V8, SpiderMonkey, JavaScriptCore).

Manage Node versions with nvm, fnm, or volta.

Package Managers

• npm, ships with Node.

• pnpm, fast, disk-efficient (content-addressable store).

• Yarn, alternative client; v2+ uses Plug’n’Play.

$ npm install lodash
$ pnpm add -D vitest
$ yarn add express

Bundlers / Build

• Vite, modern dev server + production bundler.

• esbuild, extremely fast bundler.

• Rollup, library-focused bundler.

• webpack, still common in legacy projects.

• Turbopack / Parcel.

Linters

• ESLint, the standard linter.

$ npm install -D eslint
$ npx eslint --init
$ npx eslint src/

Formatter

• Prettier, opinionated formatter.

$ npm install -D prettier
$ npx prettier --write .

Testing

• Vitest, Vite-native, Jest-compatible.

• Jest, the long-time standard.

• Mocha + Chai, classic combo.

• Playwright / Cypress, end-to-end.

• node:test, built into Node 20+.

$ npx vitest
$ npx jest --watch

Debugging

• node --inspect-brk script.js, attach Chrome DevTools or VS Code.

• Browser DevTools, step through, inspect heap, profile.

• ndb, improved Node debugger.

Documentation

• JSDoc, generate HTML docs from doc comments.

• TypeDoc, when paired with TypeScript.

• documentation.js, modern alternative.

Editor Support

• TypeScript Language Server (works for plain JS too via checkJs: true).

• eslint and prettier plugins for VS Code, Vim, Emacs, JetBrains.

Type Checking

• TypeScript, type-check .js with // @ts-check and JSDoc, or commit to .ts.

• Flow, alternative type checker (less common today).