https://docs.npmjs.com/files/package.json

里面有介绍到 dep 的 file 字段。

文档里面找到更详细的介绍如下:

https://docs.npmjs.com/files/package.json#local-paths

Local Paths

s of version 2.0.0 you can provide a path to a local directory that contains a package. Local paths can be saved using npm install -S or npm install --save, using any of these forms:

../foo/bar
~/foo/bar
./foo/bar
/foo/bar

in which case they will be normalized to a relative path and added to yourpackage.json. For example:

{
  "name": "baz",
  "dependencies": {
    "bar": "file:../foo/bar"
  }
}

This feature is helpful for local offline development and creating tests that require npm installing where you don't want to hit an external server, but should not be used when publishing packages to the public registry.