@asamuzakjp/dom-selector

DOM Selector

A CSS selector engine.

Install

npm i @asamuzakjp/dom-selector

Usage

import { DOMSelector } from '@asamuzakjp/dom-selector';
import { JSDOM } from 'jsdom';

const { window } = new JSDOM();
const {
  closest, matches, querySelector, querySelectorAll
} = new DOMSelector(window);

matches(selector, node, opt)

matches - same functionality as Element.matches()

Parameters

• selector string CSS selector
• node object Element node
• opt object? options
  • opt.event object? instance of MouseEvent, KeyboardEvent
  • opt.noexcept boolean? no exception
  • opt.warn boolean? console warn e.g. unsupported pseudo-class

Returns boolean true if matched, false otherwise

closest(selector, node, opt)

closest - same functionality as Element.closest()

Parameters

• selector string CSS selector
• node object Element node
• opt object? options
  • opt.event object? instance of MouseEvent, KeyboardEvent
  • opt.noexcept boolean? no exception
  • opt.warn boolean? console warn e.g. unsupported pseudo-class

Returns object? matched node

querySelector(selector, node, opt)

querySelector - same functionality as Document.querySelector(), DocumentFragment.querySelector(), Element.querySelector()

Parameters

• selector string CSS selector
• node object Document, DocumentFragment or Element node
• opt object? options
  • opt.event object? instance of MouseEvent, KeyboardEvent
  • opt.noexcept boolean? no exception
  • opt.warn boolean? console warn e.g. unsupported pseudo-class

Returns object? matched node

querySelectorAll(selector, node, opt)

querySelectorAll - same functionality as Document.querySelectorAll(), DocumentFragment.querySelectorAll(), Element.querySelectorAll()
NOTE: returns Array, not NodeList

Parameters

• selector string CSS selector
• node object Document, DocumentFragment or Element node
• opt object? options
  • opt.event object? instance of MouseEvent, KeyboardEvent
  • opt.noexcept boolean? no exception
  • opt.warn boolean? console warn e.g. unsupported pseudo-class

Returns Array<(object | undefined)> array of matched nodes

Supported CSS selectors

Pattern	Supported	Note
*	✓
ns|E	✓
*|E	✓
|E	✓
E	✓
E:not(s1, s2, …)	✓
E:is(s1, s2, …)	✓
E:where(s1, s2, …)	✓
E:has(rs1, rs2, …)	✓
E.warning	✓
E#myid	✓
E[foo]	✓
E[foo="bar"]	✓
E[foo="bar" i]	✓
E[foo="bar" s]	✓
E[foo~="bar"]	✓
E[foo^="bar"]	✓
E[foo$="bar"]	✓
E[foo*="bar"]	✓
E[foo|="en"]	✓
E:defined	Partially supported	Matching with MathML is not yet supported.
E:dir(ltr)	✓
E:lang(en)	Partially supported	Comma-separated list of language codes, e.g. :lang(en, fr), is not yet supported.
E:any‑link	✓
E:link	✓
E:visited	✓	Returns false or null to prevent fingerprinting.
E:local‑link	✓
E:target	✓
E:target‑within	✓
E:scope	✓
E:current	Unsupported
E:current(s)	Unsupported
E:past	Unsupported
E:future	Unsupported
E:active	✓	Enabled if a mousedown / pointerdown event is passed as an option.
E:hover	✓	Enabled if a mouseover / pointerover event is passed as an option.
E:focus	✓
E:focus‑within	✓
E:focus‑visible	✓	Enabled if a keydown event is passed as an option.
E:open E:closed	Partially supported	Matching with <select>, e.g. select:open, is not supported.
E:enabled E:disabled	✓
E:read‑write E:read‑only	✓
E:placeholder‑shown	✓
E:default	✓
E:checked	✓
E:indeterminate	✓
E:valid E:invalid	✓
E:required E:optional	✓
E:blank	Unsupported
E:user‑valid E:user‑invalid	Unsupported
E:root	✓
E:empty	✓
E:nth‑child(n [of S]?)	✓
E:nth‑last‑child(n [of S]?)	✓
E:first‑child	✓
E:last‑child	✓
E:only‑child	✓
E:nth‑of‑type(n)	✓
E:nth‑last‑of‑type(n)	✓
E:first‑of‑type	✓
E:last‑of‑type	✓
E:only‑of‑type	✓
E F	✓
E > F	✓
E + F	✓
E ~ F	✓
F || E	Unsupported
E:nth‑col(n)	Unsupported
E:nth‑last‑col(n)	Unsupported
E:host	✓
E:host(s)	✓
E:host‑context(s)	✓
E:popover-open	✓
E:state(v)	✓	*1
E:host(:state(v))	✓	*1

*1: ElementInternals.states, i.e. CustomStateSet, is not implemented in jsdom, so you need to apply a patch in the custom element constructor.

class LabeledCheckbox extends window.HTMLElement {
  #internals;
  constructor() {
    super();
    this.#internals = this.attachInternals();
    // patch CustomStateSet
    if (!this.#internals.states) {
      this.#internals.states = new Set();
    }
    this.addEventListener('click', this._onClick.bind(this));
  }
  get checked() {
    return this.#internals.states.has('checked');
  }
  set checked(flag) {
    if (flag) {
      this.#internals.states.add('checked');
    } else {
      this.#internals.states.delete('checked');
    }
  }
  _onClick(event) {
    this.checked = !this.checked;
  }
}

Monkey patch jsdom

import { DOMSelector } from '@asamuzakjp/dom-selector';
import { JSDOM } from 'jsdom';

const dom = new JSDOM('', {
  runScripts: 'dangerously',
  url: 'http://localhost/',
  beforeParse: window => {
    const domSelector = new DOMSelector(window);

    const matches = domSelector.matches.bind(domSelector);
    window.Element.prototype.matches = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return matches(selector, this);
    };

    const closest = domSelector.closest.bind(domSelector);
    window.Element.prototype.closest = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return closest(selector, this);
    };

    const querySelector = domSelector.querySelector.bind(domSelector);
    window.Document.prototype.querySelector = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return querySelector(selector, this);
    };
    window.DocumentFragment.prototype.querySelector = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return querySelector(selector, this);
    };
    window.Element.prototype.querySelector = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return querySelector(selector, this);
    };

    const querySelectorAll = domSelector.querySelectorAll.bind(domSelector);
    window.Document.prototype.querySelectorAll = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return querySelectorAll(selector, this);
    };
    window.DocumentFragment.prototype.querySelectorAll = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return querySelectorAll(selector, this);
    };
    window.Element.prototype.querySelectorAll = function (...args) {
      if (!args.length) {
        throw new window.TypeError('1 argument required, but only 0 present.');
      }
      const [selector] = args;
      return querySelectorAll(selector, this);
    };
  }
});

Performance

See benchmark for the latest results.

F: Failed because the selector is not supported or the result was incorrect.

matches()

Selector	jsdom v24.1.1 (nwsapi)	happy-dom	linkeDom	patched-jsdom (dom-selector)	Result
simple selector: matches('.content')	989,454 ops/sec ±1.51%	7,613 ops/sec ±1.10%	9,516 ops/sec ±0.60%	848,327 ops/sec ±0.66%	jsdom is the fastest and 1.2 times faster than patched-jsdom.
compound selector: matches('p.content[id]:is(:last-child, :only-child)')	602,507 ops/sec ±0.32%	7,328 ops/sec ±0.81%	9,052 ops/sec ±0.48%	405,877 ops/sec ±0.15%	jsdom is the fastest and 1.5 times faster than patched-jsdom.
compound selector: matches('p.content[id]:is(:invalid-nth-child, :only-child)')	F	7,365 ops/sec ±0.90%	F	66,159 ops/sec ±0.98%	patched-jsdom is the fastest.
compound selector: matches('p.content[id]:not(:is(.foo, .bar))')	479,695 ops/sec ±1.60%	7,470 ops/sec ±0.57%	8,804 ops/sec ±0.44%	346,257 ops/sec ±0.31%	jsdom is the fastest and 1.4 times faster than patched-jsdom.
complex selector: matches('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner > .content')	154,869 ops/sec ±0.80%	F	5,845 ops/sec ±0.34%	132,313 ops/sec ±0.22%	jsdom is the fastest and 1.2 times faster than patched-jsdom.
complex selector: matches('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner:has(> .content)')	F	F	5,754 ops/sec ±1.33%	21,105 ops/sec ±1.16%	patched-jsdom is the fastest.
complex selector within logical pseudo-class: matches(':is(.box > .content, .block > .content)')	411,631 ops/sec ±0.31%	F	6,123 ops/sec ±0.38%	340,899 ops/sec ±0.19%	jsdom is the fastest and 1.2 times faster than patched-jsdom.

closest()

Selector	jsdom v24.1.1 (nwsapi)	happy-dom	linkeDom	patched-jsdom (dom-selector)	Result
simple selector: closest('.container')	379,529 ops/sec ±0.13%	7,469 ops/sec ±1.56%	9,306 ops/sec ±0.72%	346,182 ops/sec ±1.52%	jsdom is the fastest and 1.1 times faster than patched-jsdom.
compound selector: closest('div.container[id]:not(.foo, .box)')	137,674 ops/sec ±1.76%	F	8,696 ops/sec ±0.72%	125,138 ops/sec ±1.62%	jsdom is the fastest and 1.1 times faster than patched-jsdom.
complex selector: closest('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner > .content')	142,675 ops/sec ±0.43%	F	5,804 ops/sec ±0.87%	122,213 ops/sec ±1.38%	jsdom is the fastest and 1.2 times faster than patched-jsdom.
complex selector: closest('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner:has(> .content)')	F	F	5,733 ops/sec ±0.87%	17,024 ops/sec ±0.74%	patched-jsdom is the fastest.
complex selector within logical pseudo-class: closest(':is(.container > .content, .container > .box)')	200,172 ops/sec ±1.51%	4,808 ops/sec ±1.19%	6,145 ops/sec ±0.53%	176,908 ops/sec ±1.42%	jsdom is the fastest and 1.1 times faster than patched-jsdom.

querySelector()

Selector	jsdom v24.1.1 (nwsapi)	happy-dom	linkeDom	patched-jsdom (dom-selector)	Result
simple selector: querySelector('.content')	28,846 ops/sec ±0.23%	9,426 ops/sec ±0.83%	10,729 ops/sec ±0.58%	29,550 ops/sec ±0.89%	patched-jsdom is the fastest. patched-jsdom is 1.0 times faster than jsdom.
compound selector: querySelector('p.content[id]:is(:last-child, :only-child)')	10,152 ops/sec ±0.29%	9,270 ops/sec ±0.75%	10,907 ops/sec ±0.62%	9,682 ops/sec ±1.47%	linkedom is the fastest and 1.1 times faster than patched-jsdom. jsdom is 1.0 times faster than patched-jsdom.
complex selector: querySelector('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner > .content')	229 ops/sec ±1.41%	F	1,319 ops/sec ±1.57%	281 ops/sec ±0.46%	linkedom is the fastest and 4.7 times faster than patched-jsdom. patched-jsdom is 1.2 times faster than jsdom.
complex selector: querySelector('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner:has(> .content)')	F	F	1,606 ops/sec ±1.47%	803 ops/sec ±1.47%	linkedom is the fastest and 2.0 times faster than patched-jsdom.
complex selector within logical pseudo-class: querySelector(':is(.box > .content, .block > .content)')	3,246 ops/sec ±1.58%	F	9,831 ops/sec ±0.80%	153,338 ops/sec ±1.76%	patched-jsdom is the fastest. patched-jsdom is 47.2 times faster than jsdom.

querySelectorAll()

Selector	jsdom v24.1.1 (nwsapi)	happy-dom	linkeDom	patched-jsdom (dom-selector)	Result
simple selector: querySelectorAll('.content')	2,660 ops/sec ±1.25%	782 ops/sec ±0.27%	1,234 ops/sec ±1.40%	3,276 ops/sec ±0.90%	patched-jsdom is the fastest. patched-jsdom is 1.2 times faster than jsdom.
compound selector: querySelectorAll('p.content[id]:is(:last-child, :only-child)')	977 ops/sec ±1.05%	730 ops/sec ±1.55%	1,191 ops/sec ±1.07%	1,046 ops/sec ±1.11%	linkedom is the fastest and 1.1 times faster than patched-jsdom. patched-jsdom is 1.1 times faster than jsdom.
complex selector: querySelectorAll('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner > .content')	228 ops/sec ±1.21%	F	428 ops/sec ±1.36%	279 ops/sec ±1.28%	linkedom is the fastest and 1.5 times faster than patched-jsdom. patched-jsdom is 1.2 times faster than jsdom.
complex selector: querySelectorAll('.box:first-child ~ .box:nth-of-type(4n+1) + .box[id] .block.inner:has(> .content)')	F	F	465 ops/sec ±0.20%	924 ops/sec ±0.52%	patched-jsdom is the fastest.
complex selector within logical pseudo-class: querySelectorAll(':is(.box > .content, .block > .content)')	312 ops/sec ±1.25%	F	519 ops/sec ±1.57%	780 ops/sec ±2.24%	patched-jsdom is the fastest. patched-jsdom is 2.5 times faster than jsdom.

Acknowledgments

The following resources have been of great help in the development of the DOM Selector.

• CSSTree
• selery
• jsdom
• nwsapi

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Copyright (c) 2023 asamuzaK (Kazz)