yarn init

Interactively creates or updates a package.json file.

yarn init

This command walks you through an interactive session to create a package.json file. Some defaults such as the license and initial version are found in yarn’s init-* config settings.

Here’s an example of running the command inside of a directory named testdir:

$ yarn init

question name (testdir): my-awesome-package
question version (1.0.0): 
question description: The best package you will ever find.
question entry point (index.js): 
question git repository: https://github.com/yarnpkg/example-yarn-package
question author: Yarn Contributor
question license (MIT): 
success Saved package.json
✨  Done in 87.70s.

This results in the following package.json:

{
  "name": "my-awesome-package",
  "version": "1.0.0",
  "description": "The best package you will ever find.",
  "main": "index.js",
  "repository": {
    "url": "https://github.com/yarnpkg/example-yarn-package",
    "type": "git"
  },
  "author": "Yarn Contributor",
  "license": "MIT"
}

If you already have an existing package.json file, then it will use the file’s entries as defaults.

The following existing package.json:

{
  "name": "my-existing-package",
  "version": "0.1",
  "description": "I exist therefore I am.",
  "repository": {
    "url": "https://github.com/yarnpkg/example-yarn-package",
    "type": "git"
  },
  "license": "BSD-2-Clause"
}

Results in the following defaults during the interactive session:

$ yarn init

question name (my-existing-package): 
question version (0.1): 
question description (I exist therefore I am.):
question entry point (index.js): 
question git repository (https://github.com/yarnpkg/example-yarn-package): 
question author: Yarn Contributor
question license (BSD-2-Clause): 
success Saved package.json
✨  Done in 121.53s.

yarn init --yes/-y

This command skips the interactive session mentioned above and generates a package.json based on your defaults. Some defaults may be modified changing init-* config settings like mentioned above. For example, given a fresh install of Yarn and inside a yarn-example directory:

$ yarn init --yes

warning The yes flag has been set. This will automatically answer yes to all questions which may have security implications.
success Saved package.json
✨  Done in 0.09s.

Which produces the following package.json:

{
  "name": "yarn-example",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT"
}