Lerna vs pnpm: What are the differences?

Introduction

In this article, we will compare Lerna and pnpm to understand their key differences.

1. Installation and Package Management: Lerna is a tool for managing JavaScript projects with multiple packages, while pnpm is a package manager for JavaScript projects. Lerna helps with managing the versioning and dependency linking of packages within a project, while pnpm provides a fast and efficient package installation and management system.

2. Monorepo Support: Lerna is primarily focused on managing monorepos, where multiple packages are stored in a single repository. It allows for versioning, releasing, and managing the inter-package dependencies within a monorepo. On the other hand, pnpm supports both monorepos and single-package projects. It offers efficient disk space utilization by storing dependencies in a single global store, regardless of the number of projects.

3. Dependency Deduplication: Lerna does not have built-in dependency deduplication. Each package in the monorepo can have its own set of dependencies, resulting in possible duplication of dependencies across packages. On the contrary, pnpm implements dependency deduplication, where common dependencies are shared across projects, reducing the disk space usage.

4. Concurrency and Speed: Lerna operates sequentially when running commands or scripts across multiple packages. This can lead to slower execution times, especially in larger monorepo projects. In contrast, pnpm takes advantage of parallel execution, enabling faster installation and performance by leveraging parallelization.

5. Offline Support: Lerna does not provide built-in offline support for package installation. It requires an internet connection to download and install packages. On the other hand, pnpm has offline support, allowing developers to install packages even without an internet connection. It caches the downloaded packages locally, facilitating offline installations and ensuring consistent builds.

6. Integration and Ecosystem: Lerna integrates well with other tools commonly used in the JavaScript ecosystem, such as npm, Yarn, and Babel. It can work alongside these tools to provide a comprehensive package management solution. pnpm, on the other hand, is designed as an alternative to npm and Yarn, providing its own package management system while being compatible with the npm ecosystem.

In summary, Lerna is primarily focused on managing monorepos and offers versioning and dependency linking, whereas pnpm provides efficient package installation, dependency deduplication, parallel execution, offline support, and compatibility with the npm ecosystem.