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 - equivalent to Element.matches()

Parameters

• selector string CSS selector
• node object Element node
• opt object? options
  • 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 - equivalent to Element.closest()

Parameters

• selector string CSS selector
• node object Element node
• opt object? options
  • opt.noexcept boolean? no exception
  • opt.warn boolean? console warn e.g. unsupported pseudo-class

Returns object? matched node

querySelector(selector, node, opt)

querySelector - equivalent to Document.querySelector(), DocumentFragment.querySelector() and Element.querySelector()

Parameters

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

Returns object? matched node

querySelectorAll(selector, node, opt)

querySelectorAll - equivalent to Document.querySelectorAll(), DocumentFragment.querySelectorAll() and Element.querySelectorAll()
NOTE: returns Array, not NodeList

Parameters

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

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

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);
    };
  }
});

Supported CSS selectors

|Pattern|Supported|Note| |:--------|:-------:|:--------| |*|✓| | |E|✓| | |ns|E|✓| | |*|E|✓| | ||E|✓| | |E F|✓| | |E > F|✓| | |E + F|✓| | |E ~ F|✓| | |F || E|Unsupported| | |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:is(s1, s2, …)|✓| | |E:not(s1, s2, …)|✓| | |E:where(s1, s2, …)|✓| | |E:has(rs1, rs2, …)|✓| | |E:defined|Partially supported|Matching with MathML is not yet supported.| |E:dir(ltr)|✓| | |E:lang(en)|✓| | |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:hover|✓| | |E:active|✓| | |E:focus|✓| | |E:focus‑visible|✓| | |E:focus‑within|✓| | |E:current|Unsupported| | |E:current(s)|Unsupported| | |E:past|Unsupported| | |E:future|Unsupported| | |E:openE:closed|Partially supported|Matching with <select>, e.g. select:open, is not supported.| |E:popover-open|✓| | |E:enabledE:disabled|✓| | |E:read‑writeE:read‑only|✓| | |E:placeholder‑shown|✓| | |E:default|✓| | |E:checked|✓| | |E:indeterminate|✓| | |E:blank|Unsupported| | |E:validE:invalid|✓| | |E:in-rangeE:out-of-range|✓| | |E:requiredE:optional|✓| | |E:user‑validE: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:nth‑col(n)|Unsupported| | |E:nth‑last‑col(n)|Unsupported| | |CE:state(v)|✓|*1| |:host|✓| | |:host(s)|✓| | |:host(:state(v))|✓|*1| |:host:has(rs1, rs2, ...)|✓| | |:host(s):has(rs1, rs2, ...)|✓| | |:host‑context(s)|✓| | |:host‑context(s):has(rs1, rs2, ...)|✓| | |&|✓|Only supports outermost &, i.e. equivalent to :scope|

*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;
  }
}

Performance

See benchmark for the latest results.

Acknowledgments

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

• CSSTree
• selery
• jsdom
• nwsapi

Copyright (c) 2023 asamuzaK (Kazz)