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12 <h1><a href="../files/npm-folders.html">npm-folders</a></h1> <p>Folder Structures Used by npm</p>
13 <h2 id="description">DESCRIPTION</h2>
14 <p>npm puts various things on your computer. That's its job.</p>
15 <p>This document will tell you what it puts where.</p>
16 <h3 id="tl-dr">tl;dr</h3>
18 <li>Local install (default): puts stuff in <code>./node_modules</code> of the current
20 <li>Global install (with <code>-g</code>): puts stuff in /usr/local or wherever node
22 <li>Install it <strong>locally</strong> if you're going to <code>require()</code> it.</li>
23 <li>Install it <strong>globally</strong> if you're going to run it on the command line.</li>
24 <li>If you need both, then install it in both places, or use <code>npm link</code>.</li>
26 <h3 id="prefix-configuration">prefix Configuration</h3>
27 <p>The <code>prefix</code> config defaults to the location where node is installed.
28 On most systems, this is <code>/usr/local</code>, and most of the time is the same
29 as node's <code>process.installPrefix</code>.</p>
30 <p>On windows, this is the exact location of the node.exe binary. On Unix
31 systems, it's one level up, since node is typically installed at
32 <code>{prefix}/bin/node</code> rather than <code>{prefix}/node.exe</code>.</p>
33 <p>When the <code>global</code> flag is set, npm installs things into this prefix.
34 When it is not set, it uses the root of the current package, or the
35 current working directory if not in a package already.</p>
36 <h3 id="node-modules">Node Modules</h3>
37 <p>Packages are dropped into the <code>node_modules</code> folder under the <code>prefix</code>.
38 When installing locally, this means that you can
39 <code>require("packagename")</code> to load its main module, or
40 <code>require("packagename/lib/path/to/sub/module")</code> to load other modules.</p>
41 <p>Global installs on Unix systems go to <code>{prefix}/lib/node_modules</code>.
42 Global installs on Windows go to <code>{prefix}/node_modules</code> (that is, no
43 <code>lib</code> folder.)</p>
44 <p>Scoped packages are installed the same way, except they are grouped together
45 in a sub-folder of the relevant <code>node_modules</code> folder with the name of that
46 scope prefix by the @ symbol, e.g. <code>npm install @myorg/package</code> would place
47 the package in <code>{prefix}/node_modules/@myorg/package</code>. See <code><a href="../misc/scopes.html"><a href="../misc/scopes.html">scopes(7)</a></a></code> for
49 <p>If you wish to <code>require()</code> a package, then install it locally.</p>
50 <h3 id="executables">Executables</h3>
51 <p>When in global mode, executables are linked into <code>{prefix}/bin</code> on Unix,
52 or directly into <code>{prefix}</code> on Windows.</p>
53 <p>When in local mode, executables are linked into
54 <code>./node_modules/.bin</code> so that they can be made available to scripts run
55 through npm. (For example, so that a test runner will be in the path
56 when you run <code>npm test</code>.)</p>
57 <h3 id="man-pages">Man Pages</h3>
58 <p>When in global mode, man pages are linked into <code>{prefix}/share/man</code>.</p>
59 <p>When in local mode, man pages are not installed.</p>
60 <p>Man pages are not installed on Windows systems.</p>
61 <h3 id="cache">Cache</h3>
62 <p>See <code><a href="../cli/npm-cache.html"><a href="../cli/npm-cache.html">npm-cache(1)</a></a></code>. Cache files are stored in <code>~/.npm</code> on Posix, or
63 <code>~/npm-cache</code> on Windows.</p>
64 <p>This is controlled by the <code>cache</code> configuration param.</p>
65 <h3 id="temp-files">Temp Files</h3>
66 <p>Temporary files are stored by default in the folder specified by the
67 <code>tmp</code> config, which defaults to the TMPDIR, TMP, or TEMP environment
68 variables, or <code>/tmp</code> on Unix and <code>c:\windows\temp</code> on Windows.</p>
69 <p>Temp files are given a unique folder under this root for each run of the
70 program, and are deleted upon successful exit.</p>
71 <h2 id="more-information">More Information</h2>
72 <p>When installing locally, npm first tries to find an appropriate
73 <code>prefix</code> folder. This is so that <code>npm install foo@1.2.3</code> will install
74 to the sensible root of your package, even if you happen to have <code>cd</code>ed
75 into some other folder.</p>
76 <p>Starting at the $PWD, npm will walk up the folder tree checking for a
77 folder that contains either a <code>package.json</code> file, or a <code>node_modules</code>
78 folder. If such a thing is found, then that is treated as the effective
79 "current directory" for the purpose of running npm commands. (This
80 behavior is inspired by and similar to git's .git-folder seeking
81 logic when running git commands in a working dir.)</p>
82 <p>If no package root is found, then the current folder is used.</p>
83 <p>When you run <code>npm install foo@1.2.3</code>, then the package is loaded into
84 the cache, and then unpacked into <code>./node_modules/foo</code>. Then, any of
85 foo's dependencies are similarly unpacked into
86 <code>./node_modules/foo/node_modules/...</code>.</p>
87 <p>Any bin files are symlinked to <code>./node_modules/.bin/</code>, so that they may
88 be found by npm scripts when necessary.</p>
89 <h3 id="global-installation">Global Installation</h3>
90 <p>If the <code>global</code> configuration is set to true, then npm will
91 install packages "globally".</p>
92 <p>For global installation, packages are installed roughly the same way,
93 but using the folders described above.</p>
94 <h3 id="cycles-conflicts-and-folder-parsimony">Cycles, Conflicts, and Folder Parsimony</h3>
95 <p>Cycles are handled using the property of node's module system that it
96 walks up the directories looking for <code>node_modules</code> folders. So, at every
97 stage, if a package is already installed in an ancestor <code>node_modules</code>
98 folder, then it is not installed at the current location.</p>
99 <p>Consider the case above, where <code>foo -> bar -> baz</code>. Imagine if, in
100 addition to that, baz depended on bar, so you'd have:
101 <code>foo -> bar -> baz -> bar -> baz ...</code>. However, since the folder
102 structure is: <code>foo/node_modules/bar/node_modules/baz</code>, there's no need to
103 put another copy of bar into <code>.../baz/node_modules</code>, since when it calls
104 require("bar"), it will get the copy that is installed in
105 <code>foo/node_modules/bar</code>.</p>
106 <p>This shortcut is only used if the exact same
107 version would be installed in multiple nested <code>node_modules</code> folders. It
108 is still possible to have <code>a/node_modules/b/node_modules/a</code> if the two
109 "a" packages are different versions. However, without repeating the
110 exact same package multiple times, an infinite regress will always be
112 <p>Another optimization can be made by installing dependencies at the
113 highest level possible, below the localized "target" folder.</p>
114 <h4 id="example">Example</h4>
115 <p>Consider this dependency graph:</p>
119 | +-- blerg@1.x (latest=1.3.7)
122 | | `-- bar@1.2.3 (cycle)
127 </code></pre><p>In this case, we might expect a folder structure like this:</p>
130 +-- blerg (1.2.5) <---[A]
131 +-- bar (1.2.3) <---[B]
133 | +-- baz (2.0.2) <---[C]
137 `-- baz (1.2.3) <---[D]
139 `-- quux (3.2.0) <---[E]
140 </code></pre><p>Since foo depends directly on <code>bar@1.2.3</code> and <code>baz@1.2.3</code>, those are
141 installed in foo's <code>node_modules</code> folder.</p>
142 <p>Even though the latest copy of blerg is 1.3.7, foo has a specific
143 dependency on version 1.2.5. So, that gets installed at [A]. Since the
144 parent installation of blerg satisfies bar's dependency on <code>blerg@1.x</code>,
145 it does not install another copy under [B].</p>
146 <p>Bar [B] also has dependencies on baz and asdf, so those are installed in
147 bar's <code>node_modules</code> folder. Because it depends on <code>baz@2.x</code>, it cannot
148 re-use the <code>baz@1.2.3</code> installed in the parent <code>node_modules</code> folder [D],
149 and must install its own copy [C].</p>
150 <p>Underneath bar, the <code>baz -> quux -> bar</code> dependency creates a cycle.
151 However, because bar is already in quux's ancestry [B], it does not
152 unpack another copy of bar into that folder.</p>
153 <p>Underneath <code>foo -> baz</code> [D], quux's [E] folder tree is empty, because its
154 dependency on bar is satisfied by the parent folder copy installed at [B].</p>
155 <p>For a graphical breakdown of what is installed where, use <code>npm ls</code>.</p>
156 <h3 id="publishing">Publishing</h3>
157 <p>Upon publishing, npm will look in the <code>node_modules</code> folder. If any of
158 the items there are not in the <code>bundledDependencies</code> array, then they will
159 not be included in the package tarball.</p>
160 <p>This allows a package maintainer to install all of their dependencies
161 (and dev dependencies) locally, but only re-publish those items that
162 cannot be found elsewhere. See <code><a href="../files/package.json.html"><a href="../files/package.json.html">package.json(5)</a></a></code> for more information.</p>
163 <h2 id="see-also">SEE ALSO</h2>
165 <li><a href="../misc/npm-faq.html"><a href="../misc/npm-faq.html">npm-faq(7)</a></a></li>
166 <li><a href="../files/package.json.html"><a href="../files/package.json.html">package.json(5)</a></a></li>
167 <li><a href="../cli/npm-install.html"><a href="../cli/npm-install.html">npm-install(1)</a></a></li>
168 <li><a href="../cli/npm-pack.html"><a href="../cli/npm-pack.html">npm-pack(1)</a></a></li>
169 <li><a href="../cli/npm-cache.html"><a href="../cli/npm-cache.html">npm-cache(1)</a></a></li>
170 <li><a href="../cli/npm-config.html"><a href="../cli/npm-config.html">npm-config(1)</a></a></li>
171 <li><a href="../files/npmrc.html"><a href="../files/npmrc.html">npmrc(5)</a></a></li>
172 <li><a href="../misc/npm-config.html"><a href="../misc/npm-config.html">npm-config(7)</a></a></li>
173 <li><a href="../cli/npm-publish.html"><a href="../cli/npm-publish.html">npm-publish(1)</a></a></li>
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187 <p id="footer">npm-global — npm@2.11.2</p>