# Package Managers (npm, yarn, pnpm)
Confidence: high
Last verified: 2026-05-22
Generation: human_only


## TL;DR

Package managers automate dependency installation, version management, and script execution. npm (Node Package Manager) is the default for Node.js with 2M+ packages. Yarn (Facebook, 2016) added deterministic installs via lockfiles. pnpm (2017) saves disk space via content-addressable storage (symlinked node_modules).

## Core Explanation

`package.json`: dependencies (runtime), devDependencies (build/test), peerDependencies (host provides), optionalDependencies. Semantic versioning (semver): MAJOR.MINOR.PATCH. `^1.2.3` allows minor/patch updates; `~1.2.3` allows patch only. `package-lock.json` pins exact versions for reproducible builds. `npx` runs packages without installing.

## Further Reading

- [npm Documentation](https://docs.npmjs.com/)