@netlify/parse-domain/README.md

Splits an url into sub-domain, domain and effective top-level-domain

parse-domain
============
**Splits a URL into sub-domain, domain and the top-level domain.**

[![](https://img.shields.io/npm/v/parse-domain.svg)](https://www.npmjs.com/package/parse-domain)
[![](https://img.shields.io/npm/dm/parse-domain.svg)](https://www.npmjs.com/package/parse-domain)
[![Dependency Status](https://david-dm.org/peerigon/parse-domain.svg)](https://david-dm.org/peerigon/parse-domain)
[![Build Status](https://travis-ci.org/peerigon/parse-domain.svg?branch=master)](https://travis-ci.org/peerigon/parse-domain)
[![Coverage Status](https://img.shields.io/coveralls/peerigon/parse-domain.svg)](https://coveralls.io/r/peerigon/parse-domain?branch=master)

Since domains are handled differently across different countries and organizations, splitting a URL into sub-domain, domain and top-level-domain parts is not a simple regexp. **parse-domain** uses a [large list of known top-level domains](https://publicsuffix.org/list/public_suffix_list.dat) from publicsuffix.org to recognize different parts of the domain.

<br />

Installation
------------------------------------------------------------------------

```sh
npm install --save parse-domain
```

<br />

Usage
------------------------------------------------------------------------

```javascript
// long subdomains can be handled
expect(parseDomain("some.subdomain.example.co.uk")).to.eql({
    subdomain: "some.subdomain",
    domain: "example",
    tld: "co.uk"
});

// protocols, usernames, passwords, ports, paths, queries and hashes are disregarded
expect(parseDomain("https://user:password@example.co.uk:8080/some/path?and&query#hash")).to.eql({
    subdomain: "",
    domain: "example",
    tld: "co.uk"
});

// unknown top-level domains are ignored
expect(parseDomain("unknown.tld.kk")).to.equal(null);

// invalid urls are also ignored
expect(parseDomain("invalid url")).to.equal(null);
expect(parseDomain({})).to.equal(null);
```

### Introducing custom tlds

```javascript
// custom top-level domains can optionally be specified
expect(parseDomain("mymachine.local",{ customTlds: ["local"] })).to.eql({
    subdomain: "",
    domain: "mymachine",
    tld: "local"
});

// custom regexps can optionally be specified (instead of customTlds)
expect(parseDomain("localhost",{ customTlds:/localhost|\.local/ })).to.eql({
    subdomain: "",
    domain: "",
    tld: "localhost"
});
```

It can sometimes be helpful to apply the customTlds argument using a helper function

```javascript
function parseLocalDomains(url) {
    return parseDomain(url, {
        customTlds: /localhost|\.local/
    });
}

expect(parseLocalDomains("localhost")).to.eql({
    subdomain: "",
    domain: "",
    tld: "localhost"
});
expect(parseLocalDomains("mymachine.local")).to.eql({
    subdomain: "",
    domain: "mymachine",
    tld: "local"
});
```

<br />

API
------------------------------------------------------------------------

### `parseDomain(url: string, options: ParseOptions): ParsedDomain|null`

Returns `null` if `url` has an unknown tld or if it's not a valid url.

#### `ParseOptions`

```javascript
{
    // A list of custom tlds that are first matched against the url.
    // Useful if you also need to split internal URLs like localhost.
    customTlds: RegExp|Array<string>,
    
    // There are lot of private domains that act like top-level domains,
    // like blogspot.com, googleapis.com or s3.amazonaws.com.
    // By default, these domains would be split into:
    // { subdomain: ..., domain: "blogspot", tld: "com" }
    // When this flag is set to true, the domain will be split into
    // { subdomain: ..., domain: ..., tld: "blogspot.com" }
    // See also https://github.com/peerigon/parse-domain/issues/4
    privateTlds: boolean - default: false
}
```

#### `ParsedDomain`

```javascript
{
    tld: string,
    domain: string,
    subdomain: string
}
```

<br />

License
------------------------------------------------------------------------

Unlicense

## Sponsors

[<img src="https://assets.peerigon.com/peerigon/logo/peerigon-logo-flat-spinat.png" width="150" />](https://peerigon.com)