npm-developers - Developer Guide
So, you´ve decided to use npm to develop (and maybe publish/deploy) your project.
There are a few things that you need to do above the simple steps that your users will do
to install your program.
About These Documents
These are man pages. If you install npm, you should be able to then do man npm-thing to
get the documentation on a particular topic, or npm help thing to see the same informa‐
What is a <code>package</code>
A package is:
· a) a folder containing a program described by a package.json file
· b) a gzipped tarball containing (a)
· c) a url that resolves to (b)
· d) a <name>@<version> that is published on the registry with (c)
· e) a <name>@<tag> that points to (d)
· f) a <name> that has a "latest" tag satisfying (e)
· g) a git url that, when cloned, results in (a).
Even if you never publish your package, you can still get a lot of benefits of using npm
if you just want to write a node program (a), and perhaps if you also want to be able to
easily install it elsewhere after packing it up into a tarball (b).
Git urls can be of the form:
The commit-ish can be any tag, sha, or branch which can be supplied as an argument to git
checkout. The default is master.
The package.json File
You need to have a package.json file in the root of your project to do much of anything
with npm. That is basically the whole interface.
See npm help 5 package.json for details about what goes in that file. At the very least,
name This should be a string that identifies your project. Please do not use the name to
to explicitly state the versions of node (or whatever else) that your program
It does not necessarily need to match your github repository name.
So, node-foo and bar-js are bad names. foo or bar are better.
A semver-compatible version.
Specify the versions of node (or whatever else) that your program runs on. The node
API changes a lot, and there may be bugs or new functionality that you depend on.
author Take some credit.
If you have a special compilation or installation script, then you should put it in
the scripts object. You should definitely have at least a basic smoke-test command
as the "scripts.test" field. See npm help 7 scripts.
main If you have a single module that serves as the entry point to your program (like
what the "foo" package gives you at require("foo")), then you need to specify that
in the "main" field.
This is an object mapping names to folders. The best ones to include are "lib" and
"doc", but if you use "man" to specify a folder full of man pages, they´ll get
installed just like these ones.
You can use npm init in the root of your package in order to get you started with a pretty
basic package.json file. See npm help npm-init for more info.
Keeping files <em>out</em> of your package
Use a .npmignore file to keep stuff out of your package. If there´s no .npmignore file,
but there is a .gitignore file, then npm will ignore the stuff matched by the .gitignore
file. If you want to include something that is excluded by your .gitignore file, you can
create an empty .npmignore file to override it. Like git, npm looks for .npmignore and
.gitignore files in all subdirectories of your package, not only the root directory.
.npmignore files follow the same pattern rules
ing-Files as .gitignore files:
· Blank lines or lines starting with # are ignored.
· Standard glob patterns work.
· You can end patterns with a forward slash / to specify a directory.
· You can negate a pattern by starting it with an exclamation point !.
By default, the following paths and files are ignored, so there´s no need to add them to
Additionally, everything in node_modules is ignored, except for bundled dependencies. npm
automatically handles this for you, so don´t bother adding node_modules to .npmignore.
The following paths and files are never ignored, so adding them to .npmignore is point‐
· README (and its variants)
· CHANGELOG (and its variants)
· LICENSE / LICENCE
npm link is designed to install a development package and see the changes in real time
without having to keep re-installing it. (You do need to either re-link or npm rebuild -g
to update compiled packages, of course.)
More info at npm help npm-link.
Before Publishing: Make Sure Your Package Installs and Works
This is important.
If you can not install it locally, you´ll have problems trying to publish it. Or, worse
yet, you´ll be able to publish it, but you´ll be publishing a broken or pointless package.
So don´t do that.
In the root of your package, do this:
npm install . -g
That´ll show you that it´s working. If you´d rather just create a symlink package that
points to your working directory, then do this:
Use npm ls -g to see if it´s there.
To test a local install, go into some other folder, and then do:
npm install ../my-package
to install it locally into the node_modules folder in that other place.
Then go into the node-repl, and try using require("my-thing") to bring in your module´s
Create a User Account
Create a user with the adduser command. It works like this:
and then follow the prompts.
This is documented better in npm help adduser.
Publish your package
This part´s easy. In the root of your folder, do this:
You can give publish a url to a tarball, or a filename of a tarball, or a path to a
Note that pretty much everything in that folder will be exposed by default. So, if you
have secret stuff in there, use a .npmignore file to list out the globs to ignore, or pub‐
lish from a fresh checkout.
Brag about it
Send emails, write blogs, blab in IRC.
Tell the world how easy it is to install your program!
· npm help 7 faq
· npm help npm
· npm help init
· npm help 5 package.json
· npm help 7 scripts
· npm help publish
· npm help adduser
· npm help 7 registry
December 2015 NPM-DEVELOPERS(7)