@socketregistry/packageurl-js

TypeScript Package URL (purl) parser and builder. Drop-in replacement for packageurl-js with full type safety, zero dependencies, and spec compliance with the Package URL specification.

What is a PURL?

A Package URL (purl) standardizes how to identify software packages:

pkg:npm/lodash@4.17.21
pkg:pypi/requests@2.28.1
pkg:maven/org.springframework/spring-core@5.3.21

Format breakdown:

  pkg:type/namespace/name@version?qualifiers#subpath
  │   │    │         │    │       │          │
  │   │    │         │    │       │          └─ Optional subpath
  │   │    │         │    │       └──────────── Optional key=value pairs
  │   │    │         │    └──────────────────── Optional version
  │   │    │         └───────────────────────── Required package name
  │   │    └─────────────────────────────────── Optional namespace/scope
  │   └──────────────────────────────────────── Required package type
  └──────────────────────────────────────────── Scheme (always "pkg:")

Supports 35+ ecosystems: npm, pypi, maven, gem, cargo, nuget, composer, golang, docker, and more.

Features

• ✅ Modular & tree-shakeable - Import only what you need
• ✅ Full TypeScript support - Comprehensive type exports
• ✅ Zero dependencies - Lightweight and secure
• ✅ Spec compliant - Follows purl-spec
• ✅ 100% test coverage - Over 1,000 passing tests
• ✅ Multiple APIs - Functional, class-based, and builder patterns
• ✅ URL conversion - Convert to repository and download URLs
• ✅ Registry checks - Verify package existence across 14 registries

Install

pnpm install @socketregistry/packageurl-js

Drop-in replacement via package override:

{
  "pnpm": {
    "overrides": {
      "packageurl-js": "npm:@socketregistry/packageurl-js@^1"
    }
  }
}

Requirements: Node >= 18.20.4

Usage

Modular Functions (Tree-shakeable)

Parse npm specifiers:

import { parseNpmSpecifier } from '@socketregistry/packageurl-js'

parseNpmSpecifier('lodash@4.17.21')
// -> { namespace: undefined, name: 'lodash', version: '4.17.21' }

parseNpmSpecifier('@babel/core@^7.0.0')
// -> { namespace: '@babel', name: 'core', version: '7.0.0' }

Stringify PURLs:

import { stringify } from '@socketregistry/packageurl-js'

stringify(purl)
// -> 'pkg:npm/lodash@4.17.21'

Compare PURLs:

import { equals, compare } from '@socketregistry/packageurl-js'

equals(purl1, purl2)  // -> boolean
compare(purl1, purl2) // -> -1 | 0 | 1

Class API

Parse and build:

import { PackageURL } from '@socketregistry/packageurl-js'

// Parse strings
const purl = PackageURL.fromString('pkg:npm/lodash@4.17.21')
console.log(purl.name)      // 'lodash'
console.log(purl.version)   // '4.17.21'

// Parse npm specifiers
PackageURL.fromNpm('lodash@4.17.21')
PackageURL.fromNpm('@babel/core@^7.0.0')

// Constructor
new PackageURL('npm', null, 'express', '4.18.2')
// -> 'pkg:npm/express@4.18.2'

Builder pattern:

import { PurlBuilder } from '@socketregistry/packageurl-js'

PurlBuilder.npm()
  .name('lodash')
  .version('4.17.21')
  .build()
// -> 'pkg:npm/lodash@4.17.21'

URL conversion:

import { UrlConverter } from '@socketregistry/packageurl-js'

UrlConverter.toRepositoryUrl(purl)
// -> 'https://github.com/lodash/lodash'

UrlConverter.toDownloadUrl(purl)
// -> 'https://registry.npmjs.org/lodash/-/lodash-4.17.21.tgz'

Registry existence checks:

import { purlExists, npmExists } from '@socketregistry/packageurl-js'

// Check if package exists in its registry
await purlExists(purl)
// -> { exists: true, latestVersion: '4.17.21' }

// Type-specific checks (modular)
await npmExists('lodash')
await npmExists('core', '@babel')  // scoped package
await npmExists('lodash', undefined, '4.17.21')  // validate version

// Supported registries:
// npmExists, pypiExists, cargoExists, gemExists,
// mavenExists, nugetExists, golangExists, packagistExists,
// cocoapodsExists, pubExists, hexExists, cpanExists,
// cranExists, hackageExists

TypeScript Types

All types are exported for maximum flexibility:

import type {
  PackageURLObject,
  NpmPackageComponents,
  ParsedPurlComponents,
  QualifiersObject,
  ComponentEncoder,
  DownloadUrl,
  RepositoryUrl,
} from '@socketregistry/packageurl-js'

// Type-safe npm package parsing
const components: NpmPackageComponents = parseNpmSpecifier('lodash@4.17.21')

// Type-safe PURL objects
const obj: PackageURLObject = purl.toObject()

Constants:

import { PurlQualifierNames, PURL_Type } from '@socketregistry/packageurl-js'

// Standard qualifier keys
PurlQualifierNames.Checksum       // 'checksum'
PurlQualifierNames.RepositoryUrl  // 'repository_url'

// Package types
PURL_Type.NPM    // 'npm'
PURL_Type.PYPI   // 'pypi'

See docs/types.md for complete type reference.

API Reference

• docs/api.md - Complete API documentation
• docs/types.md - TypeScript type reference

Development

Quick commands:

pnpm install   # Install dependencies
pnpm build     # Build
pnpm test      # Test
pnpm check     # Lint + typecheck

License

MIT