Local node_modules folder should use hard links instead of copying from global cache when on the same partition

[dsherret]

As a first pass, we are copying files from the global cache to the local node_modules folder, but when the two locations are on the same partition, we could hard link them instead.

[youk]

I guess this was never addressed? It is sort of annoyance when using Deno with tools like Vite. AFAICS there is no straightforward way to avoid node_modules here, so each Vite+Deno project consumes unnecessary space.

[dsherret]

Oh, we use hardlinks nowadays. Are you on mac by chance?

[dsherret]

Ref: #23980

[youk]

On Windows I can see that packages are still copied to node_modules. For example:

deno -A npm:create-vite test-app --template vue-ts
cd test-app
deno install

Symlinks are created inside node_modules, but they point to the locations inside that same node_modules, e.g. node_modules\typescript -> node_modules\.deno\typescript@5.6.3\node_modules\typescript.

[dsherret]

@youk those symlinks point at hardlinks on windows if on the same device. For me, this is the output where you can see two folders sharing the file in the cache:

> fsutil hardlink list "node_modules\.deno\typescript@5.6.3\node_modules\typescript\package.json"
\.cache\deno\npm\registry.npmjs.org\typescript\5.6.3\package.json
\ts-ast-viewer\node_modules\.deno\typescript@5.6.3\node_modules\typescript\package.json
\scratch\temp\test-app\node_modules\.deno\typescript@5.6.3\node_modules\typescript\package.json

[youk]

Indeed. I wasn't looking close enough. Sorry for false report.

[dsherret]

No problem. It was an open issue 😄