PACKAGE-LOCK.JSON(5) PACKAGE-LOCK.JSON(5)
NAME
package-lock.json - A manifestation of the manifest
Description
package-lock.json is automatically generated for any operations where
npm modifies either the node_modules tree, or package.json. It
describes the exact tree that was generated, such that subsequent
installs are able to generate identical trees, regardless of
intermediate dependency updates.
This file is intended to be committed into source repositories, and
serves various purposes:
o Describe a single representation of a dependency tree such that
teammates, deployments, and continuous integration are guaranteed
to install exactly the same dependencies.
o Provide a facility for users to "time-travel" to previous states of
node_modules without having to commit the directory itself.
o Facilitate greater visibility of tree changes through readable
source control diffs.
o Optimize the installation process by allowing npm to skip repeated
metadata resolutions for previously-installed packages.
o As of npm v7, lockfiles include enough information to gain a
complete picture of the package tree, reducing the need to read
package.json files, and allowing for significant performance
improvements.
package-lock.json vs npm-shrinkwrap.json
Both of these files have the same format, and perform similar functions
in the root of a project.
The difference is that package-lock.json cannot be published, and it
will be ignored if found in any place other than the root project.
In contrast, npm-shrinkwrap.json </configuring-npm/npm-shrinkwrap-json>
allows publication, and defines the dependency tree from the point
encountered. This is not recommended unless deploying a CLI tool or
otherwise using the publication process for producing production
packages.
If both package-lock.json and npm-shrinkwrap.json are present in the
root of a project, npm-shrinkwrap.json will take precedence and
package-lock.json will be ignored.
Hidden Lockfiles
In order to avoid processing the node_modules folder repeatedly, npm as
of v7 uses a "hidden" lockfile present in node_modules/.package-
lock.json. This contains information about the tree, and is used in
lieu of reading the entire node_modules hierarchy provided that the
following conditions are met:
o All package folders it references exist in the node_modules
hierarchy.
o No package folders exist in the node_modules hierarchy that are not
listed in the lockfile.
o The modified time of the file is at least as recent as all of the
package folders it references.
That is, the hidden lockfile will only be relevant if it was created as
part of the most recent update to the package tree. If another CLI
mutates the tree in any way, this will be detected, and the hidden
lockfile will be ignored.
Note that it is possible to manually change the contents of a package
in such a way that the modified time of the package folder is
unaffected. For example, if you add a file to
node_modules/foo/lib/bar.js, then the modified time on node_modules/foo
will not reflect this change. If you are manually editing files in
node_modules, it is generally best to delete the file at
node_modules/.package-lock.json.
As the hidden lockfile is ignored by older npm versions, it does not
contain the backwards compatibility affordances present in "normal"
lockfiles. That is, it is lockfileVersion: 3, rather than
lockfileVersion: 2.
Handling Old Lockfiles
When npm detects a lockfile from npm v6 or before during the package
installation process, it is automatically updated to fetch missing
information from either the node_modules tree or (in the case of empty
node_modules trees or very old lockfile formats) the npm registry.
File Format
name
The name of the package this is a package-lock for. This will match
what's in package.json.
version
The version of the package this is a package-lock for. This will match
what's in package.json.
lockfileVersion
An integer version, starting at 1 with the version number of this
document whose semantics were used when generating this package-
lock.json.
Note that the file format changed significantly in npm v7 to track
information that would have otherwise required looking in node_modules
or the npm registry. Lockfiles generated by npm v7 will contain
lockfileVersion: 2.
o No version provided: an "ancient" shrinkwrap file from a version of
npm prior to npm v5.
o 1: The lockfile version used by npm v5 and v6.
o 2: The lockfile version used by npm v7 and v8. Backwards compatible
to v1 lockfiles.
o 3: The lockfile version used by npm v9. Backwards compatible to npm
v7.
npm will always attempt to get whatever data it can out of a lockfile,
even if it is not a version that it was designed to support.
packages
This is an object that maps package locations to an object containing
the information about that package.
The root project is typically listed with a key of "", and all other
packages are listed with their relative paths from the root project
folder.
Package descriptors have the following fields:
o version: The version found in package.json
o resolved: The place where the package was actually resolved from.
In the case of packages fetched from the registry, this will be a
url to a tarball. In the case of git dependencies, this will be the
full git url with commit sha. In the case of link dependencies,
this will be the location of the link target. registry.npmjs.org is
a magic value meaning "the currently configured registry".
o integrity: A sha512 or sha1 Standard Subresource Integrity
<https://w3c.github.io/webappsec/specs/subresourceintegrity/>
string for the artifact that was unpacked in this location.
o link: A flag to indicate that this is a symbolic link. If this is
present, no other fields are specified, since the link target will
also be included in the lockfile.
o dev, optional, devOptional: If the package is strictly part of the
devDependencies tree, then dev will be true. If it is strictly part
of the optionalDependencies tree, then optional will be set. If it
is both a dev dependency and an optional dependency of a non-dev
dependency, then devOptional will be set. (An optional dependency
of a dev dependency will have both dev and optional set.)
o inBundle: A flag to indicate that the package is a bundled
dependency.
o hasInstallScript: A flag to indicate that the package has a
preinstall, install, or postinstall script.
o hasShrinkwrap: A flag to indicate that the package has an npm-
shrinkwrap.json file.
o bin, license, engines, dependencies, optionalDependencies: fields
from package.json
dependencies
Legacy data for supporting versions of npm that use lockfileVersion: 1.
This is a mapping of package names to dependency objects. Because the
object structure is strictly hierarchical, symbolic link dependencies
are somewhat challenging to represent in some cases.
npm v7 ignores this section entirely if a packages section is present,
but does keep it up to date in order to support switching between npm
v6 and npm v7.
Dependency objects have the following fields:
o version: a specifier that varies depending on the nature of the
package, and is usable in fetching a new copy of it.
o bundled dependencies: Regardless of source, this is a version
number that is purely for informational purposes.
o registry sources: This is a version number. (eg, 1.2.3)
o git sources: This is a git specifier with resolved committish.
(eg,
https://example.com/foo/bar#115311855adb0789a0466714ed48a1499ffea97e)
o http tarball sources: This is the URL of the tarball. (eg,
https://example.com/example-1.3.0.tgz)
o local tarball sources: This is the file URL of the tarball. (eg
file:///opt/storage/example-1.3.0.tgz)
o local link sources: This is the file URL of the link. (eg
file:libs/our-module)
o integrity: A sha512 or sha1 Standard Subresource Integrity
<https://w3c.github.io/webappsec/specs/subresourceintegrity/>
string for the artifact that was unpacked in this location. For git
dependencies, this is the commit sha.
o resolved: For registry sources this is path of the tarball relative
to the registry URL. If the tarball URL isn't on the same server as
the registry URL then this is a complete URL. registry.npmjs.org is
a magic value meaning "the currently configured registry".
o bundled: If true, this is the bundled dependency and will be
installed by the parent module. When installing, this module will
be extracted from the parent module during the extract phase, not
installed as a separate dependency.
o dev: If true then this dependency is either a development
dependency ONLY of the top level module or a transitive dependency
of one. This is false for dependencies that are both a development
dependency of the top level and a transitive dependency of a non-
development dependency of the top level.
o optional: If true then this dependency is either an optional
dependency ONLY of the top level module or a transitive dependency
of one. This is false for dependencies that are both an optional
dependency of the top level and a transitive dependency of a non-
optional dependency of the top level.
o requires: This is a mapping of module name to version. This is a
list of everything this module requires, regardless of where it
will be installed. The version should match via normal matching
rules a dependency either in our dependencies or in a level higher
than us.
o dependencies: The dependencies of this dependency, exactly as at
the top level.
See also
o npm help shrinkwrap
o npm-shrinkwrap.json </configuring-npm/npm-shrinkwrap-json>
o package.json </configuring-npm/package-json>
o npm help install
June 2023 PACKAGE-LOCK.JSON(5)
npm 9.7.1 - Generated Mon Jun 12 11:06:57 CDT 2023