Why Choose pnpm Over npm? A Guide to Faster and More Efficient Package Management
When it comes to JavaScript and Node.js package management, npm has been the default for years. However, as projects grow in size and complexity, pnpm (performant npm) has emerged as a faster, more efficient alternative that resolves some fundamental issues of npm. By optimizing dependency management and storage, pnpm improves speed, reduces disk usage, and simplifies dependency resolution.
In this blog, we’ll explore what makes pnpm unique, how it solves key issues with npm, and why you might consider using it in your next project.
What is pnpm?
pnpm is a fast, disk space-saving package manager for JavaScript projects. It was created as an alternative to npm and Yarn, with a focus on optimizing performance and reducing redundancy in how packages are stored on disk. Instead of duplicating dependencies across projects, pnpm keeps a single version of each package and creates symbolic links to them across projects as needed. This approach can save significant disk space and improve dependency management for monorepos and large projects.
Key Features of pnpm
- Efficient Storage: pnpm’s unique storage model eliminates redundancy by reusing packages across projects.
- Speed: Faster installation due to caching and efficient dependency resolution.
- Strict Dependency Management: Prevents dependency issues by isolating dependencies within each project.
- Compatibility with npm and Yarn: Fully compatible with npm and Yarn commands and packages.
How pnpm Differs from npm
While npm installs each dependency directly within the node_modules folder, creating nested structures, pnpm uses a single global store and symbolic links. Let’s look at some core differences between pnpm and npm.
1. Storage Efficiency
When you install a package with npm, it copies the package files directly into your project’s node_modules folder. In a monorepo setup, multiple projects can have many duplicate dependencies, resulting in large, bloated node_modules folders.
pnpm, however, creates a global content-addressable storage for dependencies, with only one copy of each package version. Each project then references the global packages using symbolic links, which greatly reduces disk space and speeds up the installation process.
2. Strict Dependency Resolution
One of the major issues with npm is the risk of dependency conflicts, especially when a package relies on an outdated version of another dependency. npm’s flat node_modules structure can sometimes lead to hidden, hard-to-trace bugs.
pnpm enforces a strict dependency tree, ensuring each project has an isolated set of dependencies. This strictness prevents dependency conflicts, making it easier to identify and resolve issues.
3. Faster Installations
Since pnpm stores packages globally and uses symlinks, it doesn’t need to re-download dependencies for each project. By leveraging a global cache, pnpm can install dependencies much faster than npm, especially for large projects or monorepos.
Installing and Using pnpm
Installing pnpm
You can install pnpm globally with npm:
npm install -g pnpmAlternatively, if you use Homebrew:
brew install pnpmBasic Commands in pnpm
Once pnpm is installed, its commands are similar to npm. Here are a few common ones:
- Install dependencies: Installs all dependencies listed in
package.json.
pnpm install- Install a new package: Installs a package and adds it to
package.json.
pnpm add package-name- Remove a package: Removes a package from the project.
pnpm remove package-name- Run a script: Executes scripts defined in
package.json.
pnpm run script-nameWhy Choose pnpm Over npm?
1. Disk Space Savings
pnpm’s use of global storage minimizes duplicate packages, which is particularly beneficial in monorepo setups where multiple projects may depend on the same libraries. This can lead to significant savings in disk space, especially for large projects with many dependencies.
2. Speed and Performance
Because pnpm installs each package only once and uses symbolic links for subsequent installations, it’s much faster than npm. Projects with many dependencies or monorepos with multiple projects experience a noticeable speed boost in both installation and CI/CD pipelines.
3. Improved Dependency Management
pnpm’s strict dependency isolation prevents the “phantom dependency” problem, where packages that aren’t explicitly listed in package.json are available due to npm’s flat structure. With pnpm, dependencies are strictly scoped to each project, reducing the risk of version conflicts and unintended dependency usage.
4. Ideal for Monorepos
pnpm is well-suited for monorepos because of its centralized global store, where it keeps one copy of each package and creates symlinks across projects. This approach optimizes disk usage and allows for efficient dependency management across multiple packages or applications within the same repository.
Comparing pnpm with npm and Yarn
Both npm and Yarn offer modern package management solutions, and each has its advantages. Here’s a quick comparison:
Each manager has its use case, but if you’re looking for speed, efficiency, and strong dependency isolation, pnpm stands out.
Example: Migrating a Project from npm to pnpm
Migrating a project to pnpm is straightforward. Here’s a quick guide:
- Remove
node_modulesandpackage-lock.json:
rm -rf node_modules package-lock.json- Install Dependencies with pnpm: Run the following command to generate pnpm’s lockfile (
pnpm-lock.yaml) and install dependencies:
pnpm install- Update Scripts in
package.json(optional): If you’re usingnpm runcommands, you don’t need to change anything, as pnpm is fully compatible with these. However, you can replacenpmwithpnpmin scripts if you prefer.
Potential Drawbacks of pnpm
While pnpm has many advantages, it’s worth noting a few potential downsides:
- Learning Curve: The strict dependency isolation can sometimes surprise developers accustomed to npm’s flat structure. Some packages may require adjustments to work correctly.
- Compatibility with Some Packages: Although rare, some npm packages may have issues with pnpm due to differences in dependency resolution. This can usually be resolved by adjusting configurations or dependencies.
- Community Support: While growing, pnpm’s community is smaller than npm’s. Most npm packages work with pnpm, but community support for troubleshooting specific issues may be less readily available.
Conclusion
pnpm offers a compelling alternative to npm, especially for projects with heavy dependencies or monorepos. With its unique storage model, strict dependency management, and improved speed, pnpm addresses some longstanding pain points in JavaScript package management.
Key Takeaways
- Optimized Disk Usage: Reduces redundancy with a global storage model.
- Speed Boost: Faster installations due to caching and symlinks.
- Strict Dependency Isolation: Minimizes risk of version conflicts and “phantom dependencies.”
- Ideal for Monorepos: Efficiently manages dependencies across multiple projects.
For developers and teams looking for an efficient, scalable, and reliable package manager, pnpm is a fantastic choice that offers significant advantages over npm in many scenarios. Give pnpm a try in your next project, and experience a more performant and manageable development environment!
