CSE2410 Fall 2014 Bounce

.\" Generated with Ronnjs 0.3.8

.\" http://github.com/kapouer/ronnjs/

.

.TH "NPM\-JSON" "1" "April 2013" "" ""

.

.SH "NAME"

\fBnpm-json\fR \-\- Specifics of npm\'s package\.json handling

.

.SH "DESCRIPTION"

This document is all you need to know about what\'s required in your package\.json

file\.  It must be actual JSON, not just a JavaScript object literal\.

.

.P

A lot of the behavior described in this document is affected by the config

settings described in \fBnpm help config\fR\|\.

.

.SH "DEFAULT VALUES"

npm will default some values based on package contents\.

.

.IP "\(bu" 4

\fB"scripts": {"start": "node server\.js"}\fR

.

.IP

If there is a \fBserver\.js\fR file in the root of your package, then npm

will default the \fBstart\fR command to \fBnode server\.js\fR\|\.

.

.IP "\(bu" 4

\fB"scripts":{"preinstall": "node\-waf clean || true; node\-waf configure build"}\fR

.

.IP

If there is a \fBwscript\fR file in the root of your package, npm will

default the \fBpreinstall\fR command to compile using node\-waf\.

.

.IP "\(bu" 4

\fB"scripts":{"preinstall": "node\-gyp rebuild"}\fR

.

.IP

If there is a \fBbinding\.gyp\fR file in the root of your package, npm will

default the \fBpreinstall\fR command to compile using node\-gyp\.

.

.IP "\(bu" 4

\fB"contributors": [\.\.\.]\fR

.

.IP

If there is an \fBAUTHORS\fR file in the root of your package, npm will

treat each line as a \fBName <email> (url)\fR format, where email and url

are optional\.  Lines which start with a \fB#\fR or are blank, will be

ignored\.

.

.IP "" 0

.

.SH "name"

The \fImost\fR important things in your package\.json are the name and version fields\.

Those are actually required, and your package won\'t install without

them\.  The name and version together form an identifier that is assumed

to be completely unique\.  Changes to the package should come along with

changes to the version\.

.

.P

The name is what your thing is called\.  Some tips:

.

.IP "\(bu" 4

Don\'t put "js" or "node" in the name\.  It\'s assumed that it\'s js, since you\'re

writing a package\.json file, and you can specify the engine using the "engines"

field\.  (See below\.)

.

.IP "\(bu" 4

The name ends up being part of a URL, an argument on the command line, and a

folder name\. Any name with non\-url\-safe characters will be rejected\.

Also, it can\'t start with a dot or an underscore\.

.

.IP "\(bu" 4

The name will probably be passed as an argument to require(), so it should

be something short, but also reasonably descriptive\.

.

.IP "\(bu" 4

You may want to check the npm registry to see if there\'s something by that name

already, before you get too attached to it\.  http://registry\.npmjs\.org/

.

.IP "" 0

.

.SH "version"

The \fImost\fR important things in your package\.json are the name and version fields\.

Those are actually required, and your package won\'t install without

them\.  The name and version together form an identifier that is assumed

to be completely unique\.  Changes to the package should come along with

changes to the version\.

.

.P

Version must be parseable by node\-semver \fIhttps://github\.com/isaacs/node\-semver\fR, which is bundled

with npm as a dependency\.  (\fBnpm install semver\fR to use it yourself\.)

.

.P

Here\'s how npm\'s semver implementation deviates from what\'s on semver\.org:

.

.IP "\(bu" 4

Versions can start with "v"

.

.IP "\(bu" 4

A numeric item separated from the main three\-number version by a hyphen

will be interpreted as a "build" number, and will \fIincrease\fR the version\.

But, if the tag is not a number separated by a hyphen, then it\'s treated

as a pre\-release tag, and is \fIless than\fR the version without a tag\.

So, \fB0\.1\.2\-7 > 0\.1\.2\-7\-beta > 0\.1\.2\-6 > 0\.1\.2 > 0\.1\.2beta\fR

.

.IP "" 0

.

.P

This is a little bit confusing to explain, but matches what you see in practice

when people create tags in git like "v1\.2\.3" and then do "git describe" to generate

a patch version\.

.

.SH "description"

Put a description in it\.  It\'s a string\.  This helps people discover your

package, as it\'s listed in \fBnpm search\fR\|\.

.

.SH "keywords"

Put keywords in it\.  It\'s an array of strings\.  This helps people

discover your package as it\'s listed in \fBnpm search\fR\|\.

.

.SH "homepage"

The url to the project homepage\.

.

.P

\fBNOTE\fR: This is \fInot\fR the same as "url"\.  If you put a "url" field,

then the registry will think it\'s a redirection to your package that has

been published somewhere else, and spit at you\.

.

.P

Literally\.  Spit\.  I\'m so not kidding\.

.

.SH "bugs"

The url to your project\'s issue tracker and / or the email address to which

issues should be reported\. These are helpful for people who encounter issues

with your package\.

.

.P

It should look like this:

.

.IP "" 4

.

.nf

{ "url" : "http://github\.com/owner/project/issues"

, "email" : "project@hostname\.com"

}

.

.fi

.

.IP "" 0

.

.P

You can specify either one or both values\. If you want to provide only a url,

you can specify the value for "bugs" as a simple string instead of an object\.

.

.P

If a url is provided, it will be used by the \fBnpm bugs\fR command\.

.

.SH "license"

You should specify a license for your package so that people know how they are

permitted to use it, and any restrictions you\'re placing on it\.

.

.P

The simplest way, assuming you\'re using a common license such as BSD or MIT, is

to just specify the name of the license you\'re using, like this:

.

.IP "" 4

.

.nf

{ "license" : "BSD" }

.

.fi

.

.IP "" 0

.

.P

If you have more complex licensing terms, or you want to provide more detail

in your package\.json file, you can use the more verbose plural form, like this:

.

.IP "" 4

.

.nf

"licenses" : [

  { "type" : "MyLicense"

  , "url" : "http://github\.com/owner/project/path/to/license"

  }

]

.

.fi

.

.IP "" 0

.

.P

It\'s also a good idea to include a license file at the top level in your package\.

.

.SH "people fields: author, contributors"

The "author" is one person\.  "contributors" is an array of people\.  A "person"

is an object with a "name" field and optionally "url" and "email", like this:

.

.IP "" 4

.

.nf

{ "name" : "Barney Rubble"

, "email" : "b@rubble\.com"

, "url" : "http://barnyrubble\.tumblr\.com/"

}

.

.fi

.

.IP "" 0

.

.P

Or you can shorten that all into a single string, and npm will parse it for you:

.

.IP "" 4

.

.nf

"Barney Rubble <b@rubble\.com> (http://barnyrubble\.tumblr\.com/)

.

.fi

.

.IP "" 0

.

.P

Both email and url are optional either way\.

.

.P

npm also sets a top\-level "maintainers" field with your npm user info\.

.

.SH "files"

The "files" field is an array of files to include in your project\.  If

you name a folder in the array, then it will also include the files

inside that folder\. (Unless they would be ignored by another rule\.)

.

.P

You can also provide a "\.npmignore" file in the root of your package,

which will keep files from being included, even if they would be picked

up by the files array\.  The "\.npmignore" file works just like a

"\.gitignore"\.

.

.SH "main"

The main field is a module ID that is the primary entry point to your program\.

That is, if your package is named \fBfoo\fR, and a user installs it, and then does \fBrequire("foo")\fR, then your main module\'s exports object will be returned\.

.

.P

This should be a module ID relative to the root of your package folder\.

.

.P

For most modules, it makes the most sense to have a main script and often not

much else\.

.

.SH "bin"

A lot of packages have one or more executable files that they\'d like to

install into the PATH\. npm makes this pretty easy (in fact, it uses this

feature to install the "npm" executable\.)

.

.P

To use this, supply a \fBbin\fR field in your package\.json which is a map of

command name to local file name\. On install, npm will symlink that file into \fBprefix/bin\fR for global installs, or \fB\|\./node_modules/\.bin/\fR for local

installs\.

.

.P

For example, npm has this:

.

.IP "" 4

.

.nf

{ "bin" : { "npm" : "\./cli\.js" } }

.

.fi

.

.IP "" 0

.

.P

So, when you install npm, it\'ll create a symlink from the \fBcli\.js\fR script to \fB/usr/local/bin/npm\fR\|\.

.

.P

If you have a single executable, and its name should be the name

of the package, then you can just supply it as a string\.  For example:

.

.IP "" 4

.

.nf

{ "name": "my\-program"

, "version": "1\.2\.5"

, "bin": "\./path/to/program" }

.

.fi

.

.IP "" 0

.

.P

would be the same as this:

.

.IP "" 4

.

.nf

{ "name": "my\-program"

, "version": "1\.2\.5"

, "bin" : { "my\-program" : "\./path/to/program" } }

.

.fi

.

.IP "" 0

.

.SH "man"

Specify either a single file or an array of filenames to put in place for the \fBman\fR program to find\.

.

.P

If only a single file is provided, then it\'s installed such that it is the

result from \fBman <pkgname>\fR, regardless of its actual filename\.  For example:

.

.IP "" 4

.

.nf

{ "name" : "foo"

, "version" : "1\.2\.3"

, "description" : "A packaged foo fooer for fooing foos"

, "main" : "foo\.js"

, "man" : "\./man/doc\.1"

}

.

.fi

.

.IP "" 0

.

.P

would link the \fB\|\./man/doc\.1\fR file in such that it is the target for \fBman foo\fR

.

.P

If the filename doesn\'t start with the package name, then it\'s prefixed\.

So, this:

.

.IP "" 4

.

.nf

{ "name" : "foo"

, "version" : "1\.2\.3"

, "description" : "A packaged foo fooer for fooing foos"

, "main" : "foo\.js"

, "man" : [ "\./man/foo\.1", "\./man/bar\.1" ]

}

.

.fi

.

.IP "" 0

.

.P

will create files to do \fBman foo\fR and \fBman foo\-bar\fR\|\.

.

.P

Man files must end with a number, and optionally a \fB\|\.gz\fR suffix if they are

compressed\.  The number dictates which man section the file is installed into\.

.

.IP "" 4

.

.nf

{ "name" : "foo"

, "version" : "1\.2\.3"

, "description" : "A packaged foo fooer for fooing foos"

, "main" : "foo\.js"

, "man" : [ "\./man/foo\.1", "\./man/foo\.2" ]

}

.

.fi

.

.IP "" 0

.

.P

will create entries for \fBman foo\fR and \fBman 2 foo\fR

.

.SH "directories"

The CommonJS Packages \fIhttp://wiki\.commonjs\.org/wiki/Packages/1\.0\fR spec details a

few ways that you can indicate the structure of your package using a \fBdirectories\fR

hash\. If you look at npm\'s package\.json \fIhttp://registry\.npmjs\.org/npm/latest\fR,

you\'ll see that it has directories for doc, lib, and man\.

.

.P

In the future, this information may be used in other creative ways\.

.

.SS "directories\.lib"

Tell people where the bulk of your library is\.  Nothing special is done

with the lib folder in any way, but it\'s useful meta info\.

.

.SS "directories\.bin"

If you specify a "bin" directory, then all the files in that folder will

be used as the "bin" hash\.

.

.P

If you have a "bin" hash already, then this has no effect\.

.

.SS "directories\.man"

A folder that is full of man pages\.  Sugar to generate a "man" array by

walking the folder\.

.

.SS "directories\.doc"

Put markdown files in here\.  Eventually, these will be displayed nicely,

maybe, someday\.

.

.SS "directories\.example"

Put example scripts in here\.  Someday, it might be exposed in some clever way\.

.

.SH "repository"

Specify the place where your code lives\. This is helpful for people who

want to contribute\.  If the git repo is on github, then the \fBnpm docs\fR

command will be able to find you\.

.

.P

Do it like this:

.

.IP "" 4

.

.nf

"repository" :

  { "type" : "git"

  , "url" : "http://github\.com/isaacs/npm\.git"

  }

"repository" :

  { "type" : "svn"

  , "url" : "http://v8\.googlecode\.com/svn/trunk/"

  }

.

.fi

.

.IP "" 0

.

.P

The URL should be a publicly available (perhaps read\-only) url that can be handed

directly to a VCS program without any modification\.  It should not be a url to an

html project page that you put in your browser\.  It\'s for computers\.

.

.SH "scripts"

The "scripts" member is an object hash of script commands that are run

at various times in the lifecycle of your package\.  The key is the lifecycle

event, and the value is the command to run at that point\.

.

.P

See \fBnpm help scripts\fR to find out more about writing package scripts\.

.

.SH "config"

A "config" hash can be used to set configuration

parameters used in package scripts that persist across upgrades\.  For

instance, if a package had the following:

.

.IP "" 4

.

.nf

{ "name" : "foo"

, "config" : { "port" : "8080" } }

.

.fi

.

.IP "" 0

.

.P

and then had a "start" command that then referenced the \fBnpm_package_config_port\fR environment variable, then the user could

override that by doing \fBnpm config set foo:port 8001\fR\|\.

.

.P

See \fBnpm help config\fR and \fBnpm help scripts\fR for more on package

configs\.

.

.SH "dependencies"

Dependencies are specified with a simple hash of package name to version

range\. The version range is EITHER a string which has one or more

space\-separated descriptors, OR a range like "fromVersion \- toVersion"

.

.P

\fBPlease do not put test harnesses in your \fBdependencies\fR hash\.\fR  See \fBdevDependencies\fR, below\.

.

.P

Version range descriptors may be any of the following styles, where "version"

is a semver compatible version identifier\.

.

.IP "\(bu" 4

\fBversion\fR Must match \fBversion\fR exactly

.

.IP "\(bu" 4

\fB=version\fR Same as just \fBversion\fR

.

.IP "\(bu" 4

\fB>version\fR Must be greater than \fBversion\fR

.

.IP "\(bu" 4

\fB>=version\fR etc

.

.IP "\(bu" 4

\fB<version\fR

.

.IP "\(bu" 4

\fB<=version\fR

.

.IP "\(bu" 4

\fB~version\fR See \'Tilde Version Ranges\' below

.

.IP "\(bu" 4

\fB1\.2\.x\fR See \'X Version Ranges\' below

.

.IP "\(bu" 4

\fBhttp://\.\.\.\fR See \'URLs as Dependencies\' below

.

.IP "\(bu" 4

\fB*\fR Matches any version

.

.IP "\(bu" 4

\fB""\fR (just an empty string) Same as \fB*\fR

.

.IP "\(bu" 4

\fBversion1 \- version2\fR Same as \fB>=version1 <=version2\fR\|\.

.

.IP "\(bu" 4

\fBrange1 || range2\fR Passes if either range1 or range2 are satisfied\.

.

.IP "\(bu" 4

\fBgit\.\.\.\fR See \'Git URLs as Dependencies\' below

.

.IP "" 0

.

.P

For example, these are all valid:

.

.IP "" 4

.

.nf

{ "dependencies" :

  { "foo" : "1\.0\.0 \- 2\.9999\.9999"

  , "bar" : ">=1\.0\.2 <2\.1\.2"

  , "baz" : ">1\.0\.2 <=2\.3\.4"

  , "boo" : "2\.0\.1"

  , "qux" : "<1\.0\.0 || >=2\.3\.1 <2\.4\.5 || >=2\.5\.2 <3\.0\.0"

  , "asd" : "http://asdf\.com/asdf\.tar\.gz"

  , "til" : "~1\.2"

  , "elf" : "~1\.2\.3"

  , "two" : "2\.x"

  , "thr" : "3\.3\.x"

  }

}

.

.fi

.

.IP "" 0

.

.SS "Tilde Version Ranges"

A range specifier starting with a tilde \fB~\fR character is matched against

a version in the following fashion\.

.

.IP "\(bu" 4

The version must be at least as high as the range\.

.

.IP "\(bu" 4

The version must be less than the next major revision above the range\.

.

.IP "" 0

.

.P

For example, the following are equivalent:

.

.IP "\(bu" 4

\fB"~1\.2\.3" = ">=1\.2\.3 <1\.3\.0"\fR

.

.IP "\(bu" 4

\fB"~1\.2" = ">=1\.2\.0 <1\.3\.0"\fR

.

.IP "\(bu" 4

\fB"~1" = ">=1\.0\.0 <1\.1\.0"\fR

.

.IP "" 0

.

.SS "X Version Ranges"

An "x" in a version range specifies that the version number must start

with the supplied digits, but any digit may be used in place of the x\.

.

.P

The following are equivalent:

.

.IP "\(bu" 4

\fB"1\.2\.x" = ">=1\.2\.0 <1\.3\.0"\fR

.

.IP "\(bu" 4

\fB"1\.x\.x" = ">=1\.0\.0 <2\.0\.0"\fR

.

.IP "\(bu" 4

\fB"1\.2" = "1\.2\.x"\fR

.

.IP "\(bu" 4

\fB"1\.x" = "1\.x\.x"\fR

.

.IP "\(bu" 4

\fB"1" = "1\.x\.x"\fR

.

.IP "" 0

.

.P

You may not supply a comparator with a version containing an x\.  Any

digits after the first "x" are ignored\.

.

.SS "URLs as Dependencies"

Starting with npm version 0\.2\.14, you may specify a tarball URL in place

of a version range\.

.

.P

This tarball will be downloaded and installed locally to your package at

install time\.

.

.SS "Git URLs as Dependencies"

Git urls can be of the form:

.

.IP "" 4

.

.nf

git://github\.com/user/project\.git#commit\-ish

git+ssh://user@hostname:project\.git#commit\-ish

git+ssh://user@hostname/project\.git#commit\-ish

git+http://user@hostname/project/blah\.git#commit\-ish

git+https://user@hostname/project/blah\.git#commit\-ish

.

.fi

.

.IP "" 0

.

.P

The \fBcommit\-ish\fR can be any tag, sha, or branch which can be supplied as

an argument to \fBgit checkout\fR\|\.  The default is \fBmaster\fR\|\.

.

.SH "devDependencies"

If someone is planning on downloading and using your module in their

program, then they probably don\'t want or need to download and build

the external test or documentation framework that you use\.

.

.P

In this case, it\'s best to list these additional items in a \fBdevDependencies\fR hash\.

.

.P

These things will be installed whenever the \fB\-\-dev\fR configuration flag

is set\.  This flag is set automatically when doing \fBnpm link\fR or when doing \fBnpm install\fR from the root of a package, and can be managed like any other npm

configuration param\.  See \fBnpm help config\fR for more on the topic\.

.

.SH "bundledDependencies"

Array of package names that will be bundled when publishing the package\.

.

.P

If this is spelled \fB"bundleDependencies"\fR, then that is also honorable\.

.

.SH "optionalDependencies"

If a dependency can be used, but you would like npm to proceed if it

cannot be found or fails to install, then you may put it in the \fBoptionalDependencies\fR hash\.  This is a map of package name to version

or url, just like the \fBdependencies\fR hash\.  The difference is that

failure is tolerated\.

.

.P

It is still your program\'s responsibility to handle the lack of the

dependency\.  For example, something like this:

.

.IP "" 4

.

.nf

try {

  var foo = require(\'foo\')

  var fooVersion = require(\'foo/package\.json\')\.version

} catch (er) {

  foo = null

}

if ( notGoodFooVersion(fooVersion) ) {

  foo = null

}

// \.\. then later in your program \.\.

if (foo) {

  foo\.doFooThings()

}

.

.fi

.

.IP "" 0

.

.P

Entries in \fBoptionalDependencies\fR will override entries of the same name in \fBdependencies\fR, so it\'s usually best to only put in one place\.

.

.SH "engines"

You can specify the version of node that your stuff works on:

.

.IP "" 4

.

.nf

{ "engines" : { "node" : ">=0\.1\.27 <0\.1\.30" } }

.

.fi

.

.IP "" 0

.

.P

And, like with dependencies, if you don\'t specify the version (or if you

specify "*" as the version), then any version of node will do\.

.

.P

If you specify an "engines" field, then npm will require that "node" be

somewhere on that list\. If "engines" is omitted, then npm will just assume

that it works on node\.

.

.P

You can also use the "engines" field to specify which versions of npm

are capable of properly installing your program\.  For example:

.

.IP "" 4

.

.nf

{ "engines" : { "npm" : "~1\.0\.20" } }

.

.fi

.

.IP "" 0

.

.P

Note that, unless the user has set the \fBengine\-strict\fR config flag, this

field is advisory only\.

.

.SH "engineStrict"

If you are sure that your module will \fIdefinitely not\fR run properly on

versions of Node/npm other than those specified in the \fBengines\fR hash,

then you can set \fB"engineStrict": true\fR in your package\.json file\.

This will override the user\'s \fBengine\-strict\fR config setting\.

.

.P

Please do not do this unless you are really very very sure\.  If your

engines hash is something overly restrictive, you can quite easily and

inadvertently lock yourself into obscurity and prevent your users from

updating to new versions of Node\.  Consider this choice carefully\.  If

people abuse it, it will be removed in a future version of npm\.

.

.SH "os"

You can specify which operating systems your

module will run on:

.

.IP "" 4

.

.nf

"os" : [ "darwin", "linux" ]

.

.fi

.

.IP "" 0

.

.P

You can also blacklist instead of whitelist operating systems,

just prepend the blacklisted os with a \'!\':

.

.IP "" 4

.

.nf

"os" : [ "!win32" ]

.

.fi

.

.IP "" 0

.

.P

The host operating system is determined by \fBprocess\.platform\fR

.

.P

It is allowed to both blacklist, and whitelist, although there isn\'t any

good reason to do this\.

.

.SH "cpu"

If your code only runs on certain cpu architectures,

you can specify which ones\.

.

.IP "" 4

.

.nf

"cpu" : [ "x64", "ia32" ]

.

.fi

.

.IP "" 0

.

.P

Like the \fBos\fR option, you can also blacklist architectures:

.

.IP "" 4

.

.nf

"cpu" : [ "!arm", "!mips" ]

.

.fi

.

.IP "" 0

.

.P

The host architecture is determined by \fBprocess\.arch\fR

.

.SH "preferGlobal"

If your package is primarily a command\-line application that should be

installed globally, then set this value to \fBtrue\fR to provide a warning

if it is installed locally\.

.

.P

It doesn\'t actually prevent users from installing it locally, but it

does help prevent some confusion if it doesn\'t work as expected\.

.

.SH "private"

If you set \fB"private": true\fR in your package\.json, then npm will refuse

to publish it\.

.

.P

This is a way to prevent accidental publication of private repositories\.

If you would like to ensure that a given package is only ever published

to a specific registry (for example, an internal registry),

then use the \fBpublishConfig\fR hash described below

to override the \fBregistry\fR config param at publish\-time\.

.

.SH "publishConfig"

This is a set of config values that will be used at publish\-time\.  It\'s

especially handy if you want to set the tag or registry, so that you can

ensure that a given package is not tagged with "latest" or published to

the global public registry by default\.

.

.P

Any config values can be overridden, but of course only "tag" and

"registry" probably matter for the purposes of publishing\.

.

.P

See \fBnpm help config\fR to see the list of config options that can be

overridden\.

.

.SH "SEE ALSO"

.

.IP "\(bu" 4

npm help semver

.

.IP "\(bu" 4

npm help init

.

.IP "\(bu" 4

npm help version

.

.IP "\(bu" 4

npm help config

.

.IP "\(bu" 4

npm help help

.

.IP "\(bu" 4

npm help faq

.

.IP "\(bu" 4

npm help install

.

.IP "\(bu" 4

npm help publish

.

.IP "\(bu" 4

npm help rm

.

.IP "" 0