# Working with Packages

As we are using `yarn` for managing packages, here are some helpful tips for
whenever you need to work with them.

### Install packages

To ensure you have the right version of dependencies, run this command after
cloning or switching branches.

```sh
> yarn
```

This will restore the versions stored in the lock file to the `node_modules`
folder.

### Add new packages

Rather than updating the `package.json` explicitly, you can install new
dependencies via the `yarn` command line:

```sh
# adds the package to the dependencies list
> yarn add [package-name]
# adds the package to the devDependencies list
> yarn add [package-name] --dev
```

### Updating packages

To see which packages have newer versions available:

```sh
> yarn outdated
```

To upgrade a package to its latest version:

```sh
> yarn upgrade --latest [package-name]
```

To upgrade a package to a specific version (or [version range](https://docs.npmjs.com/misc/semver#x-ranges-12x-1x-12-)):

```sh
> yarn upgrade [package-name]@[version]
```

### Removing packages

To remove any packages that are no longer needed:

```sh
> yarn remove [package-name]
```

### Upgrading Yarn

Desktop uses a local version of `yarn` to ensure one version is used on all
platforms that we develop on. To upgrade Desktop to the latest version of `yarn`:

 - download the `yarn-x-y.z.js` file from the latest release on [GitHub](https://github.com/yarnpkg/yarn/releases)
  - add it to the root `vendor` folder on disk
  - remove any previous version
  - edit `.yarnrc` to use this new version (ensuring the `x.y.z` matches the
    version you just downloaded)

```
# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
# yarn lockfile v1

yarn-path "./vendor/yarn-x.y.z.js"
```

  - edit `app/.yarnrc` to use this new version (ensuring the `x.y.z` matches the
    version you just downloaded)

```
# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
# yarn lockfile v1

yarn-path "../vendor/yarn-x.y.z.js"
```

 - Commit these changes and open a pull request to get them reviewed