publicsuffixlist.js

A JavaScript utility to make use of Mozilla Foundation's Public Suffix List ("PSL").

Why?

This is just an implementation to deal with domains while taking into account Mozilla Foundation's Public Suffix List. Follow the link to understand why such a list is needed.

Test and benchmark

npm install
npm test

Also see test and benchmark pages.

API

publicSuffixList = {
    version: '3.0',
    parse,
    getDomain,
    getPublicSuffix,
    suffixInPSL,
    toSelfie, fromSelfie,
    disableWASM, enableWASM
};

Usage

<!-- https://github.com/mathiasbynens/punycode.js -->
<script src="punycode.js"></script>
<script type="module">
import publicSuffixList from 'publicsuffixlist.js';

/* … */

// Feed it the list (you choose how you obtain it).
// `list` must be unicode text.
publicSuffixList.parse(list, punycode.toASCII);

/* … */

// Caller is responsible to pass in hostnames which are "canonicalized in the
// normal way for hostnames": lower-case, punycode, and only a-z, 0-9, -, .

let domain = publicSuffixList.getDomain('haha.whatisthis.global.prod.fastly.net');
// domain = 'whatisthis.global.prod.fastly.net'

domain = publicSuffixList.getDomain('police.uk');
// domain = ''

domain = publicSuffixList.getDomain('www.xn--85x722f.xn--55qx5d.cn');
// domain = 'xn--85x722f.xn--55qx5d.cn'

// Etc.

</script>

Node.js

npm install gorhill/publicsuffixlist.js

import suffixList from 'publicsuffixlist';
import { domainToASCII } from 'url';
import fs from 'fs';

// Suffix list downloaded from https://publicsuffix.org/list/public_suffix_list.dat
const suffixData = fs.readFileSync('./public_suffix_list.dat', 'utf8');

suffixList.parse(suffixData, domainToASCII);

let domain = suffixList.getDomain('haha.whatisthis.global.prod.fastly.net');
// domain = 'whatisthis.global.prod.fastly.net'

domain = suffixList.getDomain('police.uk');
// domain = ''

domain = suffixList.getDomain('www.xn--85x722f.xn--55qx5d.cn');
// domain = 'xn--85x722f.xn--55qx5d.cn'

Enable WebAssembly

// Browser
await publicSuffixList.enableWASM();

// Node.js
await publicSuffixList.enableWASM({
    customFetch: fileURL => {
        const buffer = fs.readFileSync(fileURL);
        return ({
            async arrayBuffer() {
                return new Uint8Array(buffer).buffer;
            }
        });
    }
});

Development

npm install
npm test
npm run docs-test
npm run show-memory-usage
npm run show-memory-usage -- --use-wasm
npm run show-memory-usage -- --heap-snapshot

Before submitting a patch, please run both npm test and npm run docs-test to make sure that there are no errors.

If a change is likely to affect memory usage, please run npm run show-memory-usage both with and without --use-wasm and share the output in the pull request description.

To analyze the heap, run npm run show-memory-usage -- --heap-snapshot and open the generated .heapsnapshot files in the browser's memory profiler.