npm-install

Install a package

Table of contents

Synopsis

npm install [<package-spec> ...]

aliases: add, i, in, ins, inst, insta, instal, isnt, isnta, isntal, isntall

Description

This command installs a package and any packages that it depends on. If the package has a package-lock, or an npm shrinkwrap file, or a yarn lock file, the installation of dependencies will be driven by that, respecting the following order of precedence:

See package-lock.json and npm shrinkwrap.

A package is:

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).

You may combine multiple arguments and even multiple types of arguments. For example:

npm install sax@">=0.1.0 <0.2.0" bench supervisor

The --tag argument will apply to all of the specified install targets. If a tag with the given name exists, the tagged version is preferred over newer versions.

The --dry-run argument will report in the usual way what the install would have done without actually installing anything.

The --package-lock-only argument will only update the package-lock.json, instead of checking node_modules and downloading dependencies.

The -f or --force argument will force npm to fetch remote resources even if a local copy exists on disk.

npm install sax --force

Configuration

See the config help doc. Many of the configuration params have some effect on installation, since that's most of what npm does.

These are some of the most common options related to installation.

save

Save installed packages to a package.json file as dependencies.

When used with the npm rm command, removes the dependency from package.json.

Will also prevent writing to package-lock.json if set to false.

save-exact

Dependencies saved to package.json will be configured with an exact version rather than using npm's default semver range operator.

global

Operates in "global" mode, so that packages are installed into the prefix folder instead of the current working directory. See folders for more on the differences in behavior.

install-strategy

Sets the strategy for installing packages in node_modules. hoisted (default): Install non-duplicated in top-level, and duplicated as necessary within directory structure. nested: (formerly --legacy-bundling) install in place, no hoisting. shallow (formerly --global-style) only install direct deps at top-level. linked: (experimental) install in node_modules/.store, link in place, unhoisted.

legacy-bundling

Instead of hoisting package installs in node_modules, install packages in the same manner that they are depended on. This may cause very deep directory structures and duplicate package installs as there is no de-duplicating. Sets --install-strategy=nested.

global-style

Only install direct dependencies in the top level node_modules, but hoist on deeper dependencies. Sets --install-strategy=shallow.

omit

Dependency types to omit from the installation tree on disk.

Note that these dependencies are still resolved and added to the package-lock.json or npm-shrinkwrap.json file. They are just not physically installed on disk.

If a package type appears in both the --include and --omit lists, then it will be included.

If the resulting omit list includes 'dev', then the NODE_ENV environment variable will be set to 'production' for all lifecycle scripts.

strict-peer-deps

If set to true, and --legacy-peer-deps is not set, then any conflicting peerDependencies will be treated as an install failure, even if npm could reasonably guess the appropriate resolution based on non-peer dependency relationships.

By default, conflicting peerDependencies deep in the dependency graph will be resolved using the nearest non-peer dependency specification, even if doing so will result in some packages receiving a peer dependency outside the range set in their package's peerDependencies object.

When such an override is performed, a warning is printed, explaining the conflict and the packages involved. If --strict-peer-deps is set, then this warning is treated as a failure.

prefer-dedupe

Prefer to deduplicate packages if possible, rather than choosing a newer version of a dependency.

package-lock

If set to false, then ignore package-lock.json files when installing. This will also prevent writing package-lock.json if save is true.

package-lock-only

If set to true, the current operation will only use the package-lock.json, ignoring node_modules.

For update this means only the package-lock.json will be updated, instead of checking node_modules and downloading dependencies.

For list this means the output will be based on the tree described by the package-lock.json, rather than the contents of node_modules.

foreground-scripts

Run all build scripts (ie, preinstall, install, and postinstall) scripts for installed packages in the foreground process, sharing standard input, output, and error with the main npm process.

Note that this will generally make installs run slower, and be much noisier, but can be useful for debugging.

ignore-scripts

If true, npm does not run scripts specified in package.json files.

Note that commands explicitly intended to run a particular script, such as npm start, npm stop, npm restart, npm test, and npm run-script will still run their intended script if ignore-scripts is set, but they will not run any pre- or post-scripts.

audit

When "true" submit audit reports alongside the current npm command to the default registry and all registries configured for scopes. See the documentation for npm audit for details on what is submitted.

Tells npm to create symlinks (or .cmd shims on Windows) for package executables.

Set to false to have it not do this. This can be used to work around the fact that some file systems don't support symlinks, even on ostensibly Unix systems.

fund

When "true" displays the message at the end of each npm install acknowledging the number of dependencies looking for funding. See npm fund for details.

dry-run

Indicates that you don't want npm to make any changes and that it should only report what it would have done. This can be passed into any of the commands that modify your local installation, eg, install, update, dedupe, uninstall, as well as pack and publish.

Note: This is NOT honored by other network related commands, eg dist-tags, owner, etc.

cpu

Override CPU architecture of native modules to install. Acceptable values are same as cpu field of package.json, which comes from process.arch.

os

Override OS of native modules to install. Acceptable values are same as os field of package.json, which comes from process.platform.

workspace

Enable running a command in the context of the configured workspaces of the current project while filtering by running only the workspaces defined by this configuration option.

Valid values for the workspace config are either:

When set for the npm init command, this may be set to the folder of a workspace which does not yet exist, to create the folder and set it up as a brand new workspace within the project.

This value is not exported to the environment for child processes.

workspaces

Set to true to run the command in the context of all configured workspaces.

Explicitly setting this to false will cause commands like install to ignore workspaces altogether. When not set explicitly:

This value is not exported to the environment for child processes.

include-workspace-root

Include the workspace root when workspaces are enabled for a command.

When false, specifying individual workspaces via the workspace config, or all workspaces via the workspaces flag, will cause npm to operate only on the specified workspaces, and not on the root project.

This value is not exported to the environment for child processes.

When set file: protocol dependencies will be packed and installed as regular dependencies instead of creating a symlink. This option has no effect on workspaces.

Algorithm

Given a package{dep} structure: A{B,C}, B{C}, C{D}, the npm install algorithm produces:

A
+-- B
+-- C
+-- D

That is, the dependency from B to C is satisfied by the fact that A already caused C to be installed at a higher level. D is still installed at the top level because nothing conflicts with it.

For A{B,C}, B{C,D@1}, C{D@2}, this algorithm produces:

A
+-- B
+-- C
   `-- D@2
+-- D@1

Because B's D@1 will be installed in the top-level, C now has to install D@2 privately for itself. This algorithm is deterministic, but different trees may be produced if two dependencies are requested for installation in a different order.

See folders for a more detailed description of the specific folder structures that npm creates.

See Also