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| <h1><a href="../files/npm-folders.html">npm-folders</a></h1> <p>Folder Structures Used by npm</p> |
| |
| <h2 id="DESCRIPTION">DESCRIPTION</h2> |
| |
| <p>npm puts various things on your computer. That's its job.</p> |
| |
| <p>This document will tell you what it puts where.</p> |
| |
| <h3 id="tl-dr">tl;dr</h3> |
| |
| <ul><li>Local install (default): puts stuff in <code>./node_modules</code> of the current |
| package root.</li><li>Global install (with <code>-g</code>): puts stuff in /usr/local or wherever node |
| is installed.</li><li>Install it <strong>locally</strong> if you're going to <code>require()</code> it.</li><li>Install it <strong>globally</strong> if you're going to run it on the command line.</li><li>If you need both, then install it in both places, or use <code>npm link</code>.</li></ul> |
| |
| <h3 id="prefix-Configuration">prefix Configuration</h3> |
| |
| <p>The <code>prefix</code> config defaults to the location where node is installed. |
| On most systems, this is <code>/usr/local</code>, and most of the time is the same |
| as node's <code>process.installPrefix</code>.</p> |
| |
| <p>On windows, this is the exact location of the node.exe binary. On Unix |
| systems, it's one level up, since node is typically installed at |
| <code>{prefix}/bin/node</code> rather than <code>{prefix}/node.exe</code>.</p> |
| |
| <p>When the <code>global</code> flag is set, npm installs things into this prefix. |
| When it is not set, it uses the root of the current package, or the |
| current working directory if not in a package already.</p> |
| |
| <h3 id="Node-Modules">Node Modules</h3> |
| |
| <p>Packages are dropped into the <code>node_modules</code> folder under the <code>prefix</code>. |
| When installing locally, this means that you can |
| <code>require("packagename")</code> to load its main module, or |
| <code>require("packagename/lib/path/to/sub/module")</code> to load other modules.</p> |
| |
| <p>Global installs on Unix systems go to <code>{prefix}/lib/node_modules</code>. |
| Global installs on Windows go to <code>{prefix}/node_modules</code> (that is, no |
| <code>lib</code> folder.)</p> |
| |
| <p>If you wish to <code>require()</code> a package, then install it locally.</p> |
| |
| <h3 id="Executables">Executables</h3> |
| |
| <p>When in global mode, executables are linked into <code>{prefix}/bin</code> on Unix, |
| or directly into <code>{prefix}</code> on Windows.</p> |
| |
| <p>When in local mode, executables are linked into |
| <code>./node_modules/.bin</code> so that they can be made available to scripts run |
| through npm. (For example, so that a test runner will be in the path |
| when you run <code>npm test</code>.)</p> |
| |
| <h3 id="Man-Pages">Man Pages</h3> |
| |
| <p>When in global mode, man pages are linked into <code>{prefix}/share/man</code>.</p> |
| |
| <p>When in local mode, man pages are not installed.</p> |
| |
| <p>Man pages are not installed on Windows systems.</p> |
| |
| <h3 id="Cache">Cache</h3> |
| |
| <p>See <code><a href="../cli/npm-cache.html">npm-cache(1)</a></code>. Cache files are stored in <code>~/.npm</code> on Posix, or |
| <code>~/npm-cache</code> on Windows.</p> |
| |
| <p>This is controlled by the <code>cache</code> configuration param.</p> |
| |
| <h3 id="Temp-Files">Temp Files</h3> |
| |
| <p>Temporary files are stored by default in the folder specified by the |
| <code>tmp</code> config, which defaults to the TMPDIR, TMP, or TEMP environment |
| variables, or <code>/tmp</code> on Unix and <code>c:\windows\temp</code> on Windows.</p> |
| |
| <p>Temp files are given a unique folder under this root for each run of the |
| program, and are deleted upon successful exit.</p> |
| |
| <h2 id="More-Information">More Information</h2> |
| |
| <p>When installing locally, npm first tries to find an appropriate |
| <code>prefix</code> folder. This is so that <code>npm install foo@1.2.3</code> will install |
| to the sensible root of your package, even if you happen to have <code>cd</code>ed |
| into some other folder.</p> |
| |
| <p>Starting at the $PWD, npm will walk up the folder tree checking for a |
| folder that contains either a <code>package.json</code> file, or a <code>node_modules</code> |
| folder. If such a thing is found, then that is treated as the effective |
| "current directory" for the purpose of running npm commands. (This |
| behavior is inspired by and similar to git's .git-folder seeking |
| logic when running git commands in a working dir.)</p> |
| |
| <p>If no package root is found, then the current folder is used.</p> |
| |
| <p>When you run <code>npm install foo@1.2.3</code>, then the package is loaded into |
| the cache, and then unpacked into <code>./node_modules/foo</code>. Then, any of |
| foo's dependencies are similarly unpacked into |
| <code>./node_modules/foo/node_modules/...</code>.</p> |
| |
| <p>Any bin files are symlinked to <code>./node_modules/.bin/</code>, so that they may |
| be found by npm scripts when necessary.</p> |
| |
| <h3 id="Global-Installation">Global Installation</h3> |
| |
| <p>If the <code>global</code> configuration is set to true, then npm will |
| install packages "globally".</p> |
| |
| <p>For global installation, packages are installed roughly the same way, |
| but using the folders described above.</p> |
| |
| <h3 id="Cycles-Conflicts-and-Folder-Parsimony">Cycles, Conflicts, and Folder Parsimony</h3> |
| |
| <p>Cycles are handled using the property of node's module system that it |
| walks up the directories looking for <code>node_modules</code> folders. So, at every |
| stage, if a package is already installed in an ancestor <code>node_modules</code> |
| folder, then it is not installed at the current location.</p> |
| |
| <p>Consider the case above, where <code>foo -> bar -> baz</code>. Imagine if, in |
| addition to that, baz depended on bar, so you'd have: |
| <code>foo -> bar -> baz -> bar -> baz ...</code>. However, since the folder |
| structure is: <code>foo/node_modules/bar/node_modules/baz</code>, there's no need to |
| put another copy of bar into <code>.../baz/node_modules</code>, since when it calls |
| require("bar"), it will get the copy that is installed in |
| <code>foo/node_modules/bar</code>.</p> |
| |
| <p>This shortcut is only used if the exact same |
| version would be installed in multiple nested <code>node_modules</code> folders. It |
| is still possible to have <code>a/node_modules/b/node_modules/a</code> if the two |
| "a" packages are different versions. However, without repeating the |
| exact same package multiple times, an infinite regress will always be |
| prevented.</p> |
| |
| <p>Another optimization can be made by installing dependencies at the |
| highest level possible, below the localized "target" folder.</p> |
| |
| <h4 id="Example">Example</h4> |
| |
| <p>Consider this dependency graph:</p> |
| |
| <pre><code>foo |
| +-- blerg@1.2.5 |
| +-- bar@1.2.3 |
| | +-- blerg@1.x (latest=1.3.7) |
| | +-- baz@2.x |
| | | `-- quux@3.x |
| | | `-- bar@1.2.3 (cycle) |
| | `-- asdf@* |
| `-- baz@1.2.3 |
| `-- quux@3.x |
| `-- bar</code></pre> |
| |
| <p>In this case, we might expect a folder structure like this:</p> |
| |
| <pre><code>foo |
| +-- node_modules |
| +-- blerg (1.2.5) <---[A] |
| +-- bar (1.2.3) <---[B] |
| | `-- node_modules |
| | +-- baz (2.0.2) <---[C] |
| | | `-- node_modules |
| | | `-- quux (3.2.0) |
| | `-- asdf (2.3.4) |
| `-- baz (1.2.3) <---[D] |
| `-- node_modules |
| `-- quux (3.2.0) <---[E]</code></pre> |
| |
| <p>Since foo depends directly on <code>bar@1.2.3</code> and <code>baz@1.2.3</code>, those are |
| installed in foo's <code>node_modules</code> folder.</p> |
| |
| <p>Even though the latest copy of blerg is 1.3.7, foo has a specific |
| dependency on version 1.2.5. So, that gets installed at [A]. Since the |
| parent installation of blerg satisfies bar's dependency on <code>blerg@1.x</code>, |
| it does not install another copy under [B].</p> |
| |
| <p>Bar [B] also has dependencies on baz and asdf, so those are installed in |
| bar's <code>node_modules</code> folder. Because it depends on <code>baz@2.x</code>, it cannot |
| re-use the <code>baz@1.2.3</code> installed in the parent <code>node_modules</code> folder [D], |
| and must install its own copy [C].</p> |
| |
| <p>Underneath bar, the <code>baz -> quux -> bar</code> dependency creates a cycle. |
| However, because bar is already in quux's ancestry [B], it does not |
| unpack another copy of bar into that folder.</p> |
| |
| <p>Underneath <code>foo -> baz</code> [D], quux's [E] folder tree is empty, because its |
| dependency on bar is satisfied by the parent folder copy installed at [B].</p> |
| |
| <p>For a graphical breakdown of what is installed where, use <code>npm ls</code>.</p> |
| |
| <h3 id="Publishing">Publishing</h3> |
| |
| <p>Upon publishing, npm will look in the <code>node_modules</code> folder. If any of |
| the items there are not in the <code>bundledDependencies</code> array, then they will |
| not be included in the package tarball.</p> |
| |
| <p>This allows a package maintainer to install all of their dependencies |
| (and dev dependencies) locally, but only re-publish those items that |
| cannot be found elsewhere. See <code><a href="../files/package.json.html">package.json(5)</a></code> for more information.</p> |
| |
| <h2 id="SEE-ALSO">SEE ALSO</h2> |
| |
| <ul><li><a href="../misc/npm-faq.html">npm-faq(7)</a></li><li><a href="../files/package.json.html">package.json(5)</a></li><li><a href="../cli/npm-install.html">npm-install(1)</a></li><li><a href="../cli/npm-pack.html">npm-pack(1)</a></li><li><a href="../cli/npm-cache.html">npm-cache(1)</a></li><li><a href="../cli/npm-config.html">npm-config(1)</a></li><li><a href="../files/npmrc.html">npmrc(5)</a></li><li><a href="../misc/npm-config.html">npm-config(7)</a></li><li><a href="../cli/npm-publish.html">npm-publish(1)</a></li></ul> |
| </div> |
| <p id="footer">npm-folders — npm@1.3.21</p> |
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