You can add apackage.json file to your package to make it easy for others to manage and install. Packages published to the registry must contain apackage.json file.

Apackage.json file:

• lists the packages your project depends on
• specifies versions of a package that your project can use usingsemantic versioning rules
• makes your build reproducible, and therefore easier to share with other developers

package.json fields

Requiredname andversion fields

Apackage.json file must contain"name" and"version" fields.

The"name" field contains your package's name andmust be lowercasewithout any spaces. May containhyphens,dots, andunderscores.

The"version" field must be in the formx.x.x and follow thesemantic versioning guidelines.

Author field

If you want inclusive package author information, in the"author" field use the following format (email and website are both optional):

Example

{
"name":"my-awesome-package",
"version":"1.0.0",
"author":"Your Name <email@example.com> (https://example.com)"
}

Creating a newpackage.json file

You can create apackage.json file by running a CLI questionnaire or creating a defaultpackage.json file.

Running a CLI questionnaire

To create apackage.json file with values that you supply, use thenpm init command.

1. On the command line, navigate to the root directory of your package.

   cd /path/to/package

2. Run the following command:

   npm init

3. Answer the questions in the command line questionnaire.

Customizing thepackage.json questionnaire

If you expect to create manypackage.json files, you can customize the questions asked and fields created during theinit process so all thepackage.json files contain a standard set of information.

1. In your home directory, create a file called.npm-init.js.

2. To add custom questions, using a text editor, add questions with theprompt function:

   module.exports = prompt("what's your favorite flavor of ice cream, buddy?", "I LIKE THEM ALL");

3. To add custom fields, using a text editor, add desired fields to the.npm-init.js file:

   module.exports={
     customField:'Example custom field',
     otherCustomField:'This example field is really cool'
   }

To learn more about creating advancednpm init customizations, see theinit-package-json GitHub repository.

Creating a defaultpackage.json file

To create a defaultpackage.json using information extracted from the current directory, use thenpm init command with the--yes or-y flag. For a list of default values, see "Default values extracted from the current directory".

1. On the command line, navigate to the root directory of your package.

   cd /path/to/package

2. Run the following command:

   npm init --yes

Example

>npm init--yes
Wrote to /home/monatheoctocat/my_package/package.json:
{
"name":"my_package",
"description":"make your package easier to find on the npm website",
"version":"1.0.0",
"scripts":{
"test":"echo\"Error: no test specified\" && exit 1"
},
"repository":{
"type":"git",
"url":"https://github.com/monatheoctocat/my_package.git"
},
"keywords":[],
"author":"",
"license":"ISC",
"bugs":{
"url":"https://github.com/monatheoctocat/my_package/issues"
},
"homepage":"https://github.com/monatheoctocat/my_package"
}

Default values extracted from the current directory

• name: the current directory name
• version: always1.0.0
• description: info about the package, or an empty string""
• scripts: by default creates an emptytest script
• keywords: empty
• author: empty
• license:ISC
• bugs: information from the current directory, if present
• homepage: information from the current directory, if present

Setting config options for the init command

You can set default config options for thenpm init command. For example, to set the default author email, author name, and license, on the command line, run the following commands:

>npmset init-author-email"example-user@example.com"
>npmset init-author-name"example_user"
>npmset init-license"MIT"

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Last edited bywraithgar onOctober 15, 2024