13 · Environments & Packaging
Package Manager
Installs the code you depend on
A tool that downloads, installs, and updates the outside code your project needs. Each language has its own: JavaScript uses npm — plus faster, disk-efficient rivals like pnpm, yarn, and bun — while Python uses pip (or newer ones like poetry and uv) and Rust uses cargo.
Concrete example
“npm install” (or “pnpm install”) pulls in every library a project lists, in one command.
Why it matters
Nobody writes everything from scratch; this is how the rest gets fetched.