pnpm

pnpm is a modern package manager for JavaScript that aims to solve common problems associated with traditional package managers like npm and Yarn, primarily focusing on speed and disk space efficiency. It achieves this by implementing a unique approach to storing dependencies: instead of duplicating packages across projects, pnpm uses a content-addressable store to save each version of a package only once on disk. When a project needs a dependency, pnpm creates hard links or symlinks to this central store, drastically reducing the overall disk footprint and speeding up installation times.

Beyond efficiency, pnpm enforces a strict `node_modules` structure. Unlike npm and Yarn (prior to Plug'n'Play), which often create a flat `node_modules` where packages can access undeclared dependencies, pnpm's non-flat structure ensures that code can only access packages explicitly listed in its `package.json`. This strictness helps prevent 'phantom dependencies' and makes projects more robust and predictable. It also offers first-class support for monorepos, simplifying the management of multiple packages within a single repository, making it an excellent choice for complex, multi-package projects.