npm, pnpm, and Yarn

npm, pnpm, and Yarn are JavaScript package managers: they resolve semver ranges from package.json, download packages from the registry, and lay out node_modules. npm ships with Node; Yarn and pnpm offer alternative install algorithms (pnpm’s content-addressable store saves disk and speeds CI). Pick based on team convention and monorepo needs—lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock) must be committed so installs are reproducible.