pnpm is a reimplementation of npm install.
npm performs its action in stages. It performs one stage for all dependencies in the tree before moving onto the next stage. In general, these are:
- Resolving: get package data and what dependencies it has. (many requests, low bandwidth)
- Fetching: fetch module contents (less requests, high bandwidth)
- Extracting: extracting module contents from .tar.gz (no network IO)
- Building: build compiled modules (no network IO)
pnpm will eagerly move onto the next stage for a module even if other modules are stuck in earlier stages. This allows pnpm to more efficiently manage network IO: for instance, it can build compiled modules in the background while resolutions/fetches are still happening.
There's more to it than this, but this is one of the big reasons.
(This article is a stub. you can help by expanding it.)
npm now maintains a flattened dependency tree as of version 3. This leads to less disk space bloat, with a messy node_modules directory as a side effect.
On the other hand, pnpm manages node_modules as an addressable storage in its store layout. This nets you the benefits of less disk space usage, while keeping your node_modules clean.
No! pnpm is not a replacement for npm; rather, think of it as a supplement to npm. It's simply a rewrite of the npm install command that uses an alternate way to store your modules. It won't reimplement other things npm is used for (publishing, node_modules management, and so on).
- You can't install from shrinkwrap (yet).
- Peer dependencies are a little trickier to deal with.
- You can't publish npm modules with
bundleDependenciesmanaged by pnpm. - Things not ticked off in the to do list are obviously not feature-complete.
Got an idea for workarounds for these issues? Share them.