tldts - Blazing Fast URL Parsing

tldts is a JavaScript library to extract hostnames, domains, public suffixes, top-level domains and subdomains from URLs.

Features:

Tuned for performance (order of 0.1 to 1 μs per input)
Handles both URLs and hostnames
Full Unicode/IDNA support
Support parsing email addresses
Detect IPv4 and IPv6 addresses
Continuously updated version of the public suffix list
TypeScript, ships with umd, esm, cjs bundles and type definitions
Small bundles and small memory footprint
Battle tested: full test coverage and production use

⚠️ If you are migrating to tldts from another library like psl, make sure to check the migration section.

Install

npm install --save tldts

Usage

Using the command-line interface:

$ npx tldts 'http://www.writethedocs.org/conf/eu/2017/'
{
  "domain": "writethedocs.org",
  "domainWithoutSuffix": "writethedocs",
  "hostname": "www.writethedocs.org",
  "isIcann": true,
  "isIp": false,
  "isPrivate": false,
  "publicSuffix": "org",
  "subdomain": "www"
}

Or from the command-line in batch:

$ echo "http://www.writethedocs.org/\nhttps://example.com" | npx tldts
{
  "domain": "writethedocs.org",
  "domainWithoutSuffix": "writethedocs",
  "hostname": "www.writethedocs.org",
  "isIcann": true,
  "isIp": false,
  "isPrivate": false,
  "publicSuffix": "org",
  "subdomain": "www"
}
{
  "domain": "example.com",
  "domainWithoutSuffix": "example",
  "hostname": "example.com",
  "isIcann": true,
  "isIp": false,
  "isPrivate": false,
  "publicSuffix": "com",
  "subdomain": ""
}

Programmatically:

const { parse } = require('tldts');

// Retrieving hostname related informations of a given URL
parse('http://www.writethedocs.org/conf/eu/2017/');
// { domain: 'writethedocs.org',
//   domainWithoutSuffix: 'writethedocs',
//   hostname: 'www.writethedocs.org',
//   isIcann: true,
//   isIp: false,
//   isPrivate: false,
//   publicSuffix: 'org',
//   subdomain: 'www' }

Modern ES6 modules import is also supported:

import { parse } from 'tldts';

Alternatively, you can try it directly in your browser here: https://npm.runkit.com/tldts

Check README.md for more details about the API.

Migrating from other libraries

TL;DR—here is a quick overview of how to use tldts to match the default behavior of the psl library. Skip to after the tables for a more detailed explanation.

	Parsing a hostname
`tldts`	`tldts.parse('spark-public.s3.amazonaws.com', { allowPrivateDomains: true })`
`psl`	`psl.parse('spark-public.s3.amazonaws.com')`
Note	Make sure to include `{ allowPrivateDomains: true }` to consider private suffixes

	Parsing a URL
`tldts`	`tldts.parse('https://spark-public.s3.amazonaws.com/data', { allowPrivateDomains: true })`
`psl`	`psl.parse(new URL('https://spark-public.s3.amazonaws.com/data').hostname)`
Note	No need to extract hostnames from URLs, `tldts` can do that for you

	Getting the domain
`tldts`	`tldts.getDomain('spark-public.s3.amazonaws.com', { allowPrivateDomains: true })`
`psl`	`psl.get('spark-public.s3.amazonaws.com')`
Note	Using specific functions like `getDomain` are more efficient then relying on `parse`

	Getting the Public Suffix
`tldts`	`tldts.getPublicSuffix('spark-public.s3.amazonaws.com', { allowPrivateDomains: true })`
`psl`	`psl.parse('spark-public.s3.amazonaws.com').tld`

Explanation. There are multiple libraries which can be used to parse URIs based on the Public Suffix List. Not all these libraries offer the same behavior by default and depending on your particular use-case, this can matter. When migrating from another library to tldts, make sure to read this section to preserve the same behavior.

The biggest difference between tldts’s default behavior and some other libraries like psl has to do with which suffixes are considered by default. The default for tldts is to only consider the ICANN section and ignore the Private section.

Consider this example using the unmaintained psl library:

const psl = require('psl');

psl.parse('https://spark-public.s3.amazonaws.com/dataanalysis/loansData.csv')
// {
//   input: 'spark-public.s3.amazonaws.com',
//   tld: 's3.amazonaws.com', <<< Public Suffix is from Private section
//   sld: 'spark-public',
//   domain: 'spark-public.s3.amazonaws.com',
//   subdomain: null,
//   listed: true
// }

And now with tldts:

const { parse } = require('tldts');

parse('spark-public.s3.amazonaws.com');
// {
//   domain: 'amazonaws.com',
//   domainWithoutSuffix: 'amazonaws',
//   hostname: 'spark-public.s3.amazonaws.com',
//   isIcann: true,
//   isIp: false,
//   isPrivate: false,
//   publicSuffix: 'com', <<< By default, use Public Suffix from ICANN section
//   subdomain: 'spark-public.s3'
// }

To get the same behavior, you need to pass the { allowPrivateDomains: true } option:

const { parse } = require('tldts');

parse('spark-public.s3.amazonaws.com', { allowPrivateDomains: true });
// {
//   domain: 'spark-public.s3.amazonaws.com',
//   domainWithoutSuffix: 'spark-public',
//   hostname: 'spark-public.s3.amazonaws.com',
//   isIcann: false,
//   isIp: false,
//   isPrivate: true,
//   publicSuffix: 's3.amazonaws.com', <<< Private Public Suffix is used
//   subdomain: ''
// }

Here are some other differences which can make your life easy. tldts accepts both hostnames and URLs as arguments, so you do not need to parse your inputs before handing them over to tldts:

const { parse } = require('tldts');

// Both are fine!
parse('spark-public.s3.amazonaws.com', { allowPrivateDomains: true });
parse('https://spark-public.s3.amazonaws.com/dataanalysis/loansData.csv', { allowPrivateDomains: true });

tldts offers dedicated methods to extract the Public Suffix, domain, subdomain, etc. without having to rely on the more generic parse function. This is also more efficient than calling parse, because less work as to be done.

const {
  getHostname,
  getDomain,
  getPublicSuffix,
  getSubdomain,
  getDomainWithoutSuffix,
} = require('tldts');

const url = 'https://spark-public.s3.amazonaws.com';

console.log(getHostname(url)); // spark-public.s3.amazonaws.com
console.log(getDomain(url, { allowPrivateDomains: true })); // spark-public.s3.amazonaws.com
console.log(getPublicSuffix(url, { allowPrivateDomains: true })); // s3.amazonaws.com
console.log(getSubdomain(url, { allowPrivateDomains: true })); // ''
console.log(getDomainWithoutSuffix(url, { allowPrivateDomains: true })); // spark-public

Contributors

tldts is based upon the excellent tld.js library and would not exist without the many contributors who worked on the project.

This project would not be possible without the amazing Mozilla’s public suffix list either. Thank you for your hard work!

License

MIT License.