1DEVELOPERS(7) DEVELOPERS(7)
2
6 developers - Developer Guide
7 Description
9 So, you've decided to use npm to develop (and maybe publish/deploy)
10 your project.
11 Fantastic!
13 There are a few things that you need to do above the simple steps that
15 your users will do to install your program.
16 About These Documents
18 These are man pages. If you install npm, you should be able to then do
19 man npm-thing to get the documentation on a particular topic, or npm
20 help thing to see the same information.
21 What is a Package
23 A package is:
24 • a) a folder containing a program described by a package.json file
26 • b) a gzipped tarball containing (a)
28 • c) a url that resolves to (b)
30 • d) a <name>@<version> that is published on the registry with (c)
32 • e) a <name>@<tag> that points to (d)
34 • f) a <name> that has a "latest" tag satisfying (e)
36 • g) a git url that, when cloned, results in (a).
38 Even if you never publish your package, you can still get a lot of ben‐
41 efits of using npm if you just want to write a node program (a), and
42 perhaps if you also want to be able to easily install it elsewhere af‐
43 ter packing it up into a tarball (b).
44 Git urls can be of the form:
46 git://github.com/user/project.git#commit-ish
48 git+ssh://user@hostname:project.git#commit-ish
49 git+http://user@hostname/project/blah.git#commit-ish
50 git+https://user@hostname/project/blah.git#commit-ish
51 The commit-ish can be any tag, sha, or branch which can be supplied as
53 an argument to git checkout. The default is whatever the repository
54 uses as its default branch.
55 The package.json File
57 You need to have a package.json file in the root of your project to do
58 much of anything with npm. That is basically the whole interface.
59 See npm help package.json for details about what goes in that file. At
61 the very least, you need:
62 • name: This should be a string that identifies your project. Please
64 do not use the name to specify that it runs on node, or is in Java‐
65 Script. You can use the "engines" field to explicitly state the ver‐
66 sions of node (or whatever else) that your program requires, and it's
67 pretty well assumed that it's JavaScript. It does not necessarily
68 need to match your github repository name. So, node-foo and bar-js
69 are bad names. foo or bar are better.
70 • version: A semver-compatible version.
72 • engines: Specify the versions of node (or whatever else) that your
74 program runs on. The node API changes a lot, and there may be bugs
75 or new functionality that you depend on. Be explicit.
76 • author: Take some credit.
78 • scripts: If you have a special compilation or installation script,
80 then you should put it in the scripts object. You should definitely
81 have at least a basic smoke-test command as the "scripts.test" field.
82 See npm help scripts.
83 • main: If you have a single module that serves as the entry point to
85 your program (like what the "foo" package gives you at re‐
86 quire("foo")), then you need to specify that in the "main" field.
87 • directories: This is an object mapping names to folders. The best
89 ones to include are "lib" and "doc", but if you use "man" to specify
90 a folder full of man pages, they'll get installed just like these
91 ones.
92 You can use npm init in the root of your package in order to get you
95 started with a pretty basic package.json file. See npm help npm init
96 for more info.
97 Keeping files out of your Package
99 Use a .npmignore file to keep stuff out of your package. If there's no
100 .npmignore file, but there is a .gitignore file, then npm will ignore
101 the stuff matched by the .gitignore file. If you want to include some‐
102 thing that is excluded by your .gitignore file, you can create an empty
103 .npmignore file to override it. Like git, npm looks for .npmignore and
104 .gitignore files in all subdirectories of your package, not only the
105 root directory.
106 .npmignore files follow the same pattern rules
108 https://git-scm.com/book/en/v2/Git-Basics-Record‐
109 ing-Changes-to-the-Repository#_ignoring as .gitignore files:
110 • Blank lines or lines starting with # are ignored.
112 • Standard glob patterns work.
114 • You can end patterns with a forward slash / to specify a directory.
116 • You can negate a pattern by starting it with an exclamation point !.
118 By default, the following paths and files are ignored, so there's no
121 need to add them to .npmignore explicitly:
122 • .*.swp
124 • ._*
126 • .DS_Store
128 • .git
130 • .hg
132 • .npmrc
134 • .lock-wscript
136 • .svn
138 • .wafpickle-*
140 • config.gypi
142 • CVS
144 • npm-debug.log
146 Additionally, everything in node_modules is ignored, except for bundled
149 dependencies. npm automatically handles this for you, so don't bother
150 adding node_modules to .npmignore.
151 The following paths and files are never ignored, so adding them to
153 .npmignore is pointless:
154 • package.json
156 • README (and its variants)
158 • CHANGELOG (and its variants)
160 • LICENSE / LICENCE
162 If, given the structure of your project, you find .npmignore to be a
165 maintenance headache, you might instead try populating the files prop‐
166 erty of package.json, which is an array of file or directory names that
167 should be included in your package. Sometimes manually picking which
168 items to allow is easier to manage than building a block list.
169 Testing whether your .npmignore or files config works
171 If you want to double check that your package will include only the
172 files you intend it to when published, you can run the npm pack command
173 locally which will generate a tarball in the working directory, the
174 same way it does for publishing.
175 Link Packages
177 npm link is designed to install a development package and see the
178 changes in real time without having to keep re-installing it. (You do
179 need to either re-link or npm rebuild -g to update compiled packages,
180 of course.)
181 More info at npm help link.
183 Before Publishing: Make Sure Your Package Installs and Works
185 This is important.
186 If you can not install it locally, you'll have problems trying to pub‐
188 lish it. Or, worse yet, you'll be able to publish it, but you'll be
189 publishing a broken or pointless package. So don't do that.
190 In the root of your package, do this:
192 npm install . -g
194 That'll show you that it's working. If you'd rather just create a sym‐
196 link package that points to your working directory, then do this:
197 npm link
199 Use npm ls -g to see if it's there.
201 To test a local install, go into some other folder, and then do:
203 cd ../some-other-folder
205 npm install ../my-package
206 to install it locally into the node_modules folder in that other place.
208 Then go into the node-repl, and try using require("my-thing") to bring
210 in your module's main module.
211 Create a User Account
213 Create a user with the adduser command. It works like this:
214 npm adduser
216 and then follow the prompts.
218 This is documented better in npm help adduser.
220 Publish your Package
222 This part's easy. In the root of your folder, do this:
223 npm publish
225 You can give publish a url to a tarball, or a filename of a tarball, or
227 a path to a folder.
228 Note that pretty much everything in that folder will be exposed by de‐
230 fault. So, if you have secret stuff in there, use a .npmignore file to
231 list out the globs to ignore, or publish from a fresh checkout.
232 Brag about it
234 Send emails, write blogs, blab in IRC.
235 Tell the world how easy it is to install your program!
237 See also
239 • npm help npm
240 • npm help init
242 • npm help package.json
244 • npm help scripts
246 • npm help publish
248 • npm help adduser
250 • npm help registry
252 October 2021 DEVELOPERS(7)