300 lines
8.8 KiB
Markdown
300 lines
8.8 KiB
Markdown
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---
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title: npm-init
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section: 1
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description: Create a package.json file
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---
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### Synopsis
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```bash
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npm init <package-spec> (same as `npx <package-spec>`)
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npm init <@scope> (same as `npx <@scope>/create`)
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aliases: create, innit
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```
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### Description
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`npm init <initializer>` can be used to set up a new or existing npm
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package.
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`initializer` in this case is an npm package named `create-<initializer>`,
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which will be installed by [`npm-exec`](/commands/npm-exec), and then have its
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main bin executed -- presumably creating or updating `package.json` and
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running any other initialization-related operations.
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The init command is transformed to a corresponding `npm exec` operation as
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follows:
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* `npm init foo` -> `npm exec create-foo`
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* `npm init @usr/foo` -> `npm exec @usr/create-foo`
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* `npm init @usr` -> `npm exec @usr/create`
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* `npm init @usr@2.0.0` -> `npm exec @usr/create@2.0.0`
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* `npm init @usr/foo@2.0.0` -> `npm exec @usr/create-foo@2.0.0`
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If the initializer is omitted (by just calling `npm init`), init will fall
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back to legacy init behavior. It will ask you a bunch of questions, and
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then write a package.json for you. It will attempt to make reasonable
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guesses based on existing fields, dependencies, and options selected. It is
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strictly additive, so it will keep any fields and values that were already
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set. You can also use `-y`/`--yes` to skip the questionnaire altogether. If
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you pass `--scope`, it will create a scoped package.
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*Note:* if a user already has the `create-<initializer>` package
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globally installed, that will be what `npm init` uses. If you want npm
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to use the latest version, or another specific version you must specify
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it:
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* `npm init foo@latest` # fetches and runs the latest `create-foo` from
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the registry
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* `npm init foo@1.2.3` # runs `create-foo@1.2.3` specifically
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#### Forwarding additional options
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Any additional options will be passed directly to the command, so `npm init
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foo -- --hello` will map to `npm exec -- create-foo --hello`.
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To better illustrate how options are forwarded, here's a more evolved
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example showing options passed to both the **npm cli** and a create package,
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both following commands are equivalent:
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- `npm init foo -y --registry=<url> -- --hello -a`
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- `npm exec -y --registry=<url> -- create-foo --hello -a`
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### Examples
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Create a new React-based project using
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[`create-react-app`](https://npm.im/create-react-app):
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```bash
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$ npm init react-app ./my-react-app
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```
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Create a new `esm`-compatible package using
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[`create-esm`](https://npm.im/create-esm):
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```bash
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$ mkdir my-esm-lib && cd my-esm-lib
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$ npm init esm --yes
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```
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Generate a plain old package.json using legacy init:
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```bash
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$ mkdir my-npm-pkg && cd my-npm-pkg
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$ git init
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$ npm init
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```
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Generate it without having it ask any questions:
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```bash
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$ npm init -y
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```
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### Workspaces support
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It's possible to create a new workspace within your project by using the
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`workspace` config option. When using `npm init -w <dir>` the cli will
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create the folders and boilerplate expected while also adding a reference
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to your project `package.json` `"workspaces": []` property in order to make
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sure that new generated **workspace** is properly set up as such.
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Given a project with no workspaces, e.g:
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```
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.
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+-- package.json
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```
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You may generate a new workspace using the legacy init:
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```bash
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$ npm init -w packages/a
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```
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That will generate a new folder and `package.json` file, while also updating
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your top-level `package.json` to add the reference to this new workspace:
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```
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.
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+-- package.json
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`-- packages
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`-- a
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`-- package.json
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```
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The workspaces init also supports the `npm init <initializer> -w <dir>`
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syntax, following the same set of rules explained earlier in the initial
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**Description** section of this page. Similar to the previous example of
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creating a new React-based project using
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[`create-react-app`](https://npm.im/create-react-app), the following syntax
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will make sure to create the new react app as a nested **workspace** within your
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project and configure your `package.json` to recognize it as such:
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```bash
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npm init -w packages/my-react-app react-app .
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```
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This will make sure to generate your react app as expected, one important
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consideration to have in mind is that `npm exec` is going to be run in the
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context of the newly created folder for that workspace, and that's the reason
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why in this example the initializer uses the initializer name followed with a
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dot to represent the current directory in that context, e.g: `react-app .`:
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```
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.
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+-- package.json
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`-- packages
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+-- a
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| `-- package.json
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`-- my-react-app
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+-- README
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+-- package.json
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`-- ...
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```
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### Configuration
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#### `yes`
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* Default: null
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* Type: null or Boolean
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Automatically answer "yes" to any prompts that npm might print on the
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command line.
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#### `force`
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* Default: false
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* Type: Boolean
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Removes various protections against unfortunate side effects, common
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mistakes, unnecessary performance degradation, and malicious input.
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* Allow clobbering non-npm files in global installs.
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* Allow the `npm version` command to work on an unclean git repository.
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* Allow deleting the cache folder with `npm cache clean`.
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* Allow installing packages that have an `engines` declaration requiring a
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different version of npm.
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* Allow installing packages that have an `engines` declaration requiring a
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different version of `node`, even if `--engine-strict` is enabled.
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* Allow `npm audit fix` to install modules outside your stated dependency
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range (including SemVer-major changes).
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* Allow unpublishing all versions of a published package.
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* Allow conflicting peerDependencies to be installed in the root project.
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* Implicitly set `--yes` during `npm init`.
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* Allow clobbering existing values in `npm pkg`
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* Allow unpublishing of entire packages (not just a single version).
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If you don't have a clear idea of what you want to do, it is strongly
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recommended that you do not use this option!
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#### `scope`
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* Default: the scope of the current project, if any, or ""
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* Type: String
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Associate an operation with a scope for a scoped registry.
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Useful when logging in to or out of a private registry:
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```
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# log in, linking the scope to the custom registry
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npm login --scope=@mycorp --registry=https://registry.mycorp.com
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# log out, removing the link and the auth token
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npm logout --scope=@mycorp
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```
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This will cause `@mycorp` to be mapped to the registry for future
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installation of packages specified according to the pattern
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`@mycorp/package`.
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This will also cause `npm init` to create a scoped package.
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```
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# accept all defaults, and create a package named "@foo/whatever",
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# instead of just named "whatever"
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npm init --scope=@foo --yes
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```
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#### `workspace`
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* Default:
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* Type: String (can be set multiple times)
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Enable running a command in the context of the configured workspaces of the
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current project while filtering by running only the workspaces defined by
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this configuration option.
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Valid values for the `workspace` config are either:
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* Workspace names
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* Path to a workspace directory
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* Path to a parent workspace directory (will result in selecting all
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workspaces within that folder)
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When set for the `npm init` command, this may be set to the folder of a
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workspace which does not yet exist, to create the folder and set it up as a
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brand new workspace within the project.
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This value is not exported to the environment for child processes.
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#### `workspaces`
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* Default: null
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* Type: null or Boolean
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Set to true to run the command in the context of **all** configured
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workspaces.
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Explicitly setting this to false will cause commands like `install` to
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ignore workspaces altogether. When not set explicitly:
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- Commands that operate on the `node_modules` tree (install, update, etc.)
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will link workspaces into the `node_modules` folder. - Commands that do
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other things (test, exec, publish, etc.) will operate on the root project,
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_unless_ one or more workspaces are specified in the `workspace` config.
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This value is not exported to the environment for child processes.
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#### `workspaces-update`
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* Default: true
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* Type: Boolean
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If set to true, the npm cli will run an update after operations that may
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possibly change the workspaces installed to the `node_modules` folder.
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#### `include-workspace-root`
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* Default: false
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* Type: Boolean
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Include the workspace root when workspaces are enabled for a command.
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When false, specifying individual workspaces via the `workspace` config, or
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all workspaces via the `workspaces` flag, will cause npm to operate only on
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the specified workspaces, and not on the root project.
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This value is not exported to the environment for child processes.
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### See Also
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* [package spec](/using-npm/package-spec)
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* [init-package-json module](http://npm.im/init-package-json)
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* [package.json](/configuring-npm/package-json)
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* [npm version](/commands/npm-version)
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* [npm scope](/using-npm/scope)
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* [npm exec](/commands/npm-exec)
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* [npm workspaces](/using-npm/workspaces)
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