How does pnpm save disk space?

pnpm saves disk space through a centralized cache and hard links, instead of copying the same packages into every project.

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#The saving mechanism

1. A single package store

• pnpm stores downloaded dependencies in one global cache (usually in ~/.pnpm-store).
• If another project needs the same package version, pnpm does not download it again.

2. Hard links instead of copies

• In node_modules, pnpm does not copy files, it creates hard links to the cache.
• As a result, the disk effectively holds one copy of each dependency, even if it is used across dozens of projects.

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#The difference from npm/Yarn

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#The practical effect

• the same React, lodash, moment, and so on are not stored hundreds of times;
• the savings can add up to dozens of gigabytes across many projects;
• installation gets faster because there are no repeat downloads or copies.

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#Conclusion

pnpm saves space through a global cache and hard links in node_modules, which eliminates dependency duplication and sharply cuts the disk space packages take up.