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sidebar_label: yarn
# dagger.io/js/yarn
Yarn is a package manager for Javascript applications
## #Package
A Yarn package
### #Package Inputs
| Name | Type | Description |
| ------------- |:-------------: |:-------------: |
|*source* | `dagger.#Artifact` |Application source code |
|*package* | `struct` |Extra alpine packages to install |
|*cwd* | `*"." \| string` |working directory to use |
|*env* | `struct` |Environment variables |
|*writeEnvFile* | `*"" \| string` |Write the contents of `environment` to this file, in the "envfile" format |
|*buildDir* | `*"build" \| string` |Read build output from this directory (path must be relative to working directory) |
|*script* | `*"build" \| string` |Run this yarn script |
|*args* | `*[] \| []` |Optional arguments for the script |
### #Package Outputs
|*build* | `struct` |Build output directory |