# Corepack

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> Stability: 1 - Experimental

_[Corepack][]_ is an experimental tool to help with
managing versions of your package managers. It exposes binary proxies for
each [supported package manager][] that, when called, will identify whatever
package manager is configured for the current project, transparently install
it if needed, and finally run it without requiring explicit user interactions.

This feature simplifies two core workflows:

* It eases new contributor onboarding, since they won't have to follow
  system-specific installation processes anymore just to have the package
  manager you want them to.

* It allows you to ensure that everyone in your team will use exactly the
  package manager version you intend them to, without them having to
  manually synchronize it each time you need to make an update.

## Workflows

### Enabling the feature

Due to its experimental status, Corepack currently needs to be explicitly
enabled to have any effect. To do that simply run [`corepack enable`][], which
will set up the symlinks in your environment, next to the `node` binary
(and overwrite the existing symlinks if necessary).

From this point forward, any call to the [supported binaries][] will work
without further setup. Should you experience a problem, just run
[`corepack disable`][] to remove the proxies from your system (and consider
opening up an issue on the [Corepack repository][] to let us know).

### Configuring a package

The Corepack proxies will find the closest [`package.json`][] file in your
current directory hierarchy to extract its [`"packageManager"`][] property.

If the value corresponds to a [supported package manager][], Corepack will make
sure that all calls to the relevant binaries are run against the requested
version, downloading it on demand if needed, and aborting if it cannot be
successfully retrieved.

### Upgrading the global versions

When running outside of an existing project (for example when running
`yarn init`), Corepack will by default use predefined versions roughly
corresponding to the latest stable releases from each tool. Those versions can
be easily overriden by running the [`corepack prepare`][] command along with the
package manager version you wish to set:

```bash
corepack prepare yarn@x.y.z --activate
```

### Offline workflow

Many production environments don't have network access. Since Corepack
usually downloads the package manager releases straight from their registries,
it can conflict with such environments. To avoid that happening, call the
[`corepack prepare`][] command while you still have network access (typically at
the same time you're preparing your deploy image). This will ensure that the
required package managers are available even without network access.

The `prepare` command has [various flags][], consult the detailed
[Corepack documentation][] for more information on the matter.

## Supported package managers

The following binaries are provided through Corepack:

| Package manager | Binary names      |
| --------------- | ----------------- |
| [Yarn][]        | `yarn`, `yarnpkg` |
| [pnpm][]        | `pnpm`, `pnpx`    |

## Common questions

### How does Corepack currently interact with npm?

While Corepack could easily support npm like any other package manager, its
shims aren't currently enabled by default. This has a few consequences:

* It's always possible to run a `npm` command within a project configured to
  be used with another package manager, since Corepack cannot intercept it.

* While `npm` is a valid option in the [`"packageManager"`][] property, the
  lack of shim will cause the global npm to be used.

### Running `npm install -g yarn` doesn't work

npm prevents accidentally overriding the Corepack binaries when doing a global
install. To avoid this problem, consider one of the following options:

* Don't run this command anymore; Corepack will provide the package manager
  binaries anyway and will ensure that the requested versions are always
  available, so installing the package managers explicitly isn't needed anymore.

* Add the `--force` flag to `npm install`; this will tell npm that it's fine to
  override binaries, but you'll erase the Corepack ones in the process (should
  that happen, run [`corepack enable`][] again to add them back).

[Corepack]: https://github.com/nodejs/corepack
[Corepack documentation]: https://github.com/nodejs/corepack#readme
[Corepack repository]: https://github.com/nodejs/corepack
[Yarn]: https://yarnpkg.com
[`"packageManager"`]: packages.md#packagemanager
[`corepack disable`]: https://github.com/nodejs/corepack#corepack-disable--name
[`corepack enable`]: https://github.com/nodejs/corepack#corepack-enable--name
[`corepack prepare`]: https://github.com/nodejs/corepack#corepack-prepare--nameversion
[`package.json`]: packages.md#nodejs-packagejson-field-definitions
[pnpm]: https://pnpm.js.org
[supported binaries]: #supported-package-managers
[supported package manager]: #supported-package-managers
[various flags]: https://github.com/nodejs/corepack#utility-commands
