package-json

What is package-json?

The package-json npm package is used to fetch metadata about a package from the npm registry without needing to download the entire package. It can be used to get the latest version of a package, its dependencies, versions, and other useful metadata.

What are package-json's main functionalities?

Get the latest version of a package

Fetches the latest version of the specified package from the npm registry.

{"packageJson": require('package-json'), "getLatestPackageVersion": async function(packageName) { const packageData = await packageJson(packageName); return packageData.version; }}

Get metadata for a specific version of a package

Retrieves metadata for a specific version of a package, including dependencies, repository information, and more.

{"packageJson": require('package-json'), "getPackageDataForVersion": async function(packageName, version) { const packageData = await packageJson(packageName, {version: version}); return packageData; }}

Get all versions of a package

Fetches a list of all available versions of a package from the npm registry.

{"packageJson": require('package-json'), "getAllVersions": async function(packageName) { const packageData = await packageJson(packageName, {allVersions: true}); return Object.keys(packageData.versions); }}

Get the full metadata of a package

Retrieves the full metadata of a package, which includes additional information that's not part of the default output, such as deprecated versions and peerDependencies.

{"packageJson": require('package-json'), "getFullMetadata": async function(packageName) { const packageData = await packageJson(packageName, {fullMetadata: true}); return packageData; }}

Other packages similar to package-json

npm-registry-fetch

Similar to package-json, npm-registry-fetch is used to make requests to the npm registry. It provides more control over the HTTP requests, such as custom headers, but it's lower-level and requires more setup compared to package-json.

pacote

Pacote is a library that can fetch metadata and tarballs from npm. It's more feature-rich than package-json, offering manifest fetching, tarball extraction, and more. It's also used internally by npm CLI.

registry-auth-token

While not directly similar, registry-auth-token is often used in conjunction with packages like package-json to handle private packages that require authentication. It retrieves the auth token for the npm registry from the user's .npmrc file.

README

package-json

Get metadata of a package from the npm registry

Install

npm install package-json

Usage

import packageJson from 'package-json';

console.log(await packageJson('ava'));
//=> {name: 'ava', …}

// Also works with scoped packages
console.log(await packageJson('@sindresorhus/df'));

API

packageJson(packageName, options?)

packageName

Type: string

Name of the package.

options

Type: object

version

Type: string
Default: latest

Package version such as 1.0.0 or a dist tag such as latest.

The version can also be in any format supported by the semver module. For example:

• 1 - Get the latest 1.x.x
• 1.2 - Get the latest 1.2.x
• ^1.2.3 - Get the latest 1.x.x but at least 1.2.3
• ~1.2.3 - Get the latest 1.2.x but at least 1.2.3

fullMetadata

Type: boolean
Default: false

By default, only an abbreviated metadata object is returned for performance reasons. Read more.

allVersions

Type: boolean
Default: false

Return the main entry containing all versions.

registryUrl

Type: string
Default: Auto-detected

The registry URL is by default inferred from the npm defaults and .npmrc. This is beneficial as package-json and any project using it will work just like npm. This option is only intended for internal tools. You should not use this option in reusable packages. Prefer just using .npmrc whenever possible.

agent

Type: object

Overwrite the agent option that is passed down to got. This might be useful to add proxy support.

PackageNotFoundError

The error thrown when the given package name cannot be found.

VersionNotFoundError

The error thrown when the given package version cannot be found.

Authentication

Both public and private registries are supported, for both scoped and unscoped packages, as long as the registry uses either bearer tokens or basic authentication.

Related

• package-json-cli - CLI for this module
• latest-version - Get the latest version of an npm package
• pkg-versions - Get the version numbers of a package from the npm registry
• npm-keyword - Get a list of npm packages with a certain keyword
• npm-user - Get user info of an npm user
• npm-email - Get the email of an npm user