3.1.2 Node.js package.json field definitions

This section describes the fields used by the Node.js runtime. Other tools (such as npm) use additional fields which are ignored by Node.js and not documented here.

‘name’

(string)

Relevant when using named imports within a package. Also used by package managers as the name of the package.

‘main’

(string)

The default module when loading the package, if exports is not specified, and in versions of Node.js prior to the introduction of exports. The "main" field defines the script that is used when the package directory is loaded via require(). Its value is a path.

require('./path/to/directory'); // This resolves to ./path/to/directory/main.js.

‘type’

(string)

The package type determining whether to load .js files as ‘CommonJS’ or ‘ES’ modules. The "type" field defines the module format that Node.js uses for all .js files that have that package.json file as their nearest parent.

The nearest parent package.json is defined as the first package.json found when searching in the current folder, that folder’s parent, and so on up until a node_modules folder or the volume root is reached.

‘exports’

(Object | string | string[])

Package exports and conditional exports. When present, limits which submodules can be loaded from within the package. The "exports" field allows defining the entry points of a package when imported by name loaded either via a node_modules lookup or a self-reference to its own name.

‘imports’

(Object)

Package imports, for use by modules within the package itself.