parse-domain

Splits a URL into sub-domain, domain and the effective top-level domain.

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 effective tld names from publicsuffix.org to recognize different parts of the domain.

Please also read the note on effective top-level domains.

Installation

npm install --save parse-domain

Usage

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

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

// non-canonical 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

// 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

function parseLocalDomains(url) {
    var options = {
        customTlds: /localhost|\.local/
    };
    return parseDomain(url, options);
}

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

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

{
    customTlds: RegExp|String[]
}

ParsedDomain

{
    tld: String,
    domain: String,
    subdomain: String
}

Note on effective top-level domains

Technically, the top-level domain is always the part after the last dot. That's why publicsuffix.org is a list of effective top-level domains: It lists all top-level domains where users are allowed to host any content. That's why foo.blogspot.com will be split into

{
    tld: "blogspot.com",
    domain: "foo",
    subdomain: ""
}

See also #4

License

Unlicense