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606 lines
16 KiB
606 lines
16 KiB
'use strict'
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const parser = require('postcss-selector-parser')
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const { default: nthCheck } = require('nth-check')
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const { getAttribute, isVElement } = require('.')
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/**
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* @typedef {object} VElementSelector
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* @property {(element: VElement)=>boolean} test
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*/
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module.exports = {
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parseSelector
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}
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/**
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* Parses CSS selectors and returns an object with a function that tests VElement.
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* @param {string} selector CSS selector
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* @param {RuleContext} context - The rule context.
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* @returns {VElementSelector}
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*/
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function parseSelector(selector, context) {
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let astSelector
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try {
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astSelector = parser().astSync(selector)
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} catch (e) {
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context.report({
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loc: { line: 0, column: 0 },
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message: `Cannot parse selector: ${selector}.`
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})
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return {
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test: () => false
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}
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}
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try {
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const test = selectorsToVElementMatcher(astSelector.nodes)
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return {
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test(element) {
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return test(element, null)
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}
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}
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} catch (e) {
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if (e instanceof SelectorError) {
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context.report({
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loc: { line: 0, column: 0 },
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message: e.message
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})
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return {
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test: () => false
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}
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}
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throw e
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}
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}
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class SelectorError extends Error {}
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/**
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* @typedef {(element: VElement, subject: VElement | null )=>boolean} VElementMatcher
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* @typedef {Exclude<parser.Selector['nodes'][number], {type:'comment'|'root'}>} ChildNode
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*/
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/**
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* Convert nodes to VElementMatcher
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* @param {parser.Selector[]} selectorNodes
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* @returns {VElementMatcher}
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*/
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function selectorsToVElementMatcher(selectorNodes) {
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const selectors = selectorNodes.map((n) =>
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selectorToVElementMatcher(cleanSelectorChildren(n))
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)
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return (element, subject) => selectors.some((sel) => sel(element, subject))
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}
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/**
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* Clean and get the selector child nodes.
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* @param {parser.Selector} selector
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* @returns {ChildNode[]}
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*/
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function cleanSelectorChildren(selector) {
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/** @type {ChildNode[]} */
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const nodes = []
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/** @type {ChildNode|null} */
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let last = null
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for (const node of selector.nodes) {
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if (node.type === 'root') {
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throw new SelectorError('Unexpected state type=root')
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}
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if (node.type === 'comment') {
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continue
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}
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if (
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(last == null || last.type === 'combinator') &&
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isDescendantCombinator(node)
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) {
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// Ignore descendant combinator
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continue
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}
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if (isDescendantCombinator(last) && node.type === 'combinator') {
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// Replace combinator
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nodes.pop()
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}
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nodes.push(node)
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last = node
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}
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if (isDescendantCombinator(last)) {
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nodes.pop()
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}
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return nodes
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/**
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* @param {parser.Node|null} node
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* @returns {node is parser.Combinator}
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*/
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function isDescendantCombinator(node) {
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return Boolean(node && node.type === 'combinator' && !node.value.trim())
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}
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}
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/**
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* Convert Selector child nodes to VElementMatcher
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* @param {ChildNode[]} selectorChildren
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* @returns {VElementMatcher}
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*/
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function selectorToVElementMatcher(selectorChildren) {
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const nodes = [...selectorChildren]
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let node = nodes.shift()
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/**
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* @type {VElementMatcher | null}
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*/
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let result = null
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while (node) {
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if (node.type === 'combinator') {
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const combinator = node.value
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node = nodes.shift()
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if (!node) {
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throw new SelectorError(`Expected selector after '${combinator}'.`)
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}
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if (node.type === 'combinator') {
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throw new SelectorError(`Unexpected combinator '${node.value}'.`)
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}
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const right = nodeToVElementMatcher(node)
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result = combination(
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result ||
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// for :has()
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((element, subject) => element === subject),
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combinator,
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right
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)
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} else {
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const sel = nodeToVElementMatcher(node)
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result = result ? compound(result, sel) : sel
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}
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node = nodes.shift()
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}
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if (!result) {
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throw new SelectorError(`Unexpected empty selector.`)
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}
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return result
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}
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/**
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* @param {VElementMatcher} left
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* @param {string} combinator
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* @param {VElementMatcher} right
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* @returns {VElementMatcher}
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*/
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function combination(left, combinator, right) {
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switch (combinator.trim()) {
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case '':
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// descendant
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return (element, subject) => {
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if (right(element, null)) {
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let parent = element.parent
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while (parent.type === 'VElement') {
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if (left(parent, subject)) {
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return true
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}
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parent = parent.parent
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}
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}
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return false
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}
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case '>':
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// child
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return (element, subject) => {
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if (right(element, null)) {
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const parent = element.parent
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if (parent.type === 'VElement') {
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return left(parent, subject)
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}
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}
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return false
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}
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case '+':
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// adjacent
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return (element, subject) => {
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if (right(element, null)) {
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const before = getBeforeElement(element)
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if (before) {
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return left(before, subject)
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}
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}
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return false
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}
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case '~':
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// sibling
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return (element, subject) => {
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if (right(element, null)) {
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for (const before of getBeforeElements(element)) {
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if (left(before, subject)) {
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return true
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}
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}
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}
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return false
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}
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default:
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throw new SelectorError(`Unknown combinator: ${combinator}.`)
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}
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}
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/**
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* Convert node to VElementMatcher
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* @param {Exclude<parser.Node, {type:'combinator'|'comment'|'root'|'selector'}>} selector
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* @returns {VElementMatcher}
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*/
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function nodeToVElementMatcher(selector) {
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switch (selector.type) {
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case 'attribute':
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return attributeNodeToVElementMatcher(selector)
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case 'class':
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return classNameNodeToVElementMatcher(selector)
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case 'id':
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return identifierNodeToVElementMatcher(selector)
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case 'tag':
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return tagNodeToVElementMatcher(selector)
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case 'universal':
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return universalNodeToVElementMatcher(selector)
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case 'pseudo':
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return pseudoNodeToVElementMatcher(selector)
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case 'nesting':
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throw new SelectorError('Unsupported nesting selector.')
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case 'string':
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throw new SelectorError(`Unknown selector: ${selector.value}.`)
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default:
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throw new SelectorError(
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`Unknown selector: ${/** @type {any}*/ (selector).value}.`
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)
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}
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}
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/**
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* Convert Attribute node to VElementMatcher
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* @param {parser.Attribute} selector
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* @returns {VElementMatcher}
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*/
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function attributeNodeToVElementMatcher(selector) {
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const key = selector.attribute
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if (!selector.operator) {
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return (element) => getAttributeValue(element, key) != null
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}
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const value = selector.value || ''
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switch (selector.operator) {
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case '=':
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return buildVElementMatcher(value, (attr, val) => attr === val)
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case '~=':
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// words
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return buildVElementMatcher(value, (attr, val) =>
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attr.split(/\s+/gu).includes(val)
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)
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case '|=':
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// immediately followed by hyphen
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return buildVElementMatcher(
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value,
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(attr, val) => attr === val || attr.startsWith(`${val}-`)
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)
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case '^=':
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// prefixed
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return buildVElementMatcher(value, (attr, val) => attr.startsWith(val))
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case '$=':
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// suffixed
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return buildVElementMatcher(value, (attr, val) => attr.endsWith(val))
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case '*=':
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// contains
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return buildVElementMatcher(value, (attr, val) => attr.includes(val))
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default:
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throw new SelectorError(`Unsupported operator: ${selector.operator}.`)
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}
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/**
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* @param {string} selectorValue
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* @param {(attrValue:string, selectorValue: string)=>boolean} test
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* @returns {VElementMatcher}
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*/
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function buildVElementMatcher(selectorValue, test) {
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const val = selector.insensitive
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? selectorValue.toLowerCase()
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: selectorValue
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return (element) => {
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const attrValue = getAttributeValue(element, key)
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if (attrValue == null) {
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return false
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}
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return test(
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selector.insensitive ? attrValue.toLowerCase() : attrValue,
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val
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)
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}
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}
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}
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/**
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* Convert ClassName node to VElementMatcher
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* @param {parser.ClassName} selector
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* @returns {VElementMatcher}
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*/
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function classNameNodeToVElementMatcher(selector) {
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const className = selector.value
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return (element) => {
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const attrValue = getAttributeValue(element, 'class')
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if (attrValue == null) {
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return false
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}
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return attrValue.split(/\s+/gu).includes(className)
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}
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}
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/**
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* Convert Identifier node to VElementMatcher
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* @param {parser.Identifier} selector
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* @returns {VElementMatcher}
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*/
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function identifierNodeToVElementMatcher(selector) {
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const id = selector.value
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return (element) => {
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const attrValue = getAttributeValue(element, 'id')
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if (attrValue == null) {
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return false
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}
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return attrValue === id
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}
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}
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/**
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* Convert Tag node to VElementMatcher
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* @param {parser.Tag} selector
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* @returns {VElementMatcher}
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*/
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function tagNodeToVElementMatcher(selector) {
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const name = selector.value
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return (element) => element.rawName === name
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}
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/**
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* Convert Universal node to VElementMatcher
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* @param {parser.Universal} _selector
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* @returns {VElementMatcher}
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*/
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function universalNodeToVElementMatcher(_selector) {
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return () => true
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}
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/**
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* Convert Pseudo node to VElementMatcher
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* @param {parser.Pseudo} selector
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* @returns {VElementMatcher}
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*/
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function pseudoNodeToVElementMatcher(selector) {
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const pseudo = selector.value
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switch (pseudo) {
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case ':not': {
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:not
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const selectors = selectorsToVElementMatcher(selector.nodes)
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return (element, subject) => {
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return !selectors(element, subject)
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}
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}
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case ':is':
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case ':where':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:is
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:where
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return selectorsToVElementMatcher(selector.nodes)
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case ':has':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:has
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return pseudoHasSelectorsToVElementMatcher(selector.nodes)
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case ':empty':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:empty
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return (element) =>
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element.children.every(
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(child) => child.type === 'VText' && !child.value.trim()
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)
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case ':nth-child': {
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-child
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const nth = parseNth(selector)
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return buildPseudoNthVElementMatcher(nth)
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}
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case ':nth-last-child': {
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-last-child
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const nth = parseNth(selector)
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return buildPseudoNthVElementMatcher((index, length) =>
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nth(length - index - 1)
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)
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}
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case ':first-child':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:first-child
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return buildPseudoNthVElementMatcher((index) => index === 0)
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case ':last-child':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:last-child
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return buildPseudoNthVElementMatcher(
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(index, length) => index === length - 1
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)
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case ':only-child':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:only-child
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return buildPseudoNthVElementMatcher(
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(index, length) => index === 0 && length === 1
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)
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case ':nth-of-type': {
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-of-type
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const nth = parseNth(selector)
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return buildPseudoNthOfTypeVElementMatcher(nth)
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}
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case ':nth-last-of-type': {
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-last-of-type
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const nth = parseNth(selector)
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return buildPseudoNthOfTypeVElementMatcher((index, length) =>
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nth(length - index - 1)
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)
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}
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case ':first-of-type':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:first-of-type
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return buildPseudoNthOfTypeVElementMatcher((index) => index === 0)
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case ':last-of-type':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:last-of-type
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return buildPseudoNthOfTypeVElementMatcher(
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(index, length) => index === length - 1
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)
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case ':only-of-type':
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// https://developer.mozilla.org/en-US/docs/Web/CSS/:only-of-type
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return buildPseudoNthOfTypeVElementMatcher(
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(index, length) => index === 0 && length === 1
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)
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default:
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throw new SelectorError(`Unsupported pseudo selector: ${pseudo}.`)
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}
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}
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/**
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* Convert :has() selector nodes to VElementMatcher
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* @param {parser.Selector[]} selectorNodes
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* @returns {VElementMatcher}
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*/
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function pseudoHasSelectorsToVElementMatcher(selectorNodes) {
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const selectors = selectorNodes.map((n) =>
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pseudoHasSelectorToVElementMatcher(n)
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)
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return (element, subject) => selectors.some((sel) => sel(element, subject))
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}
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/**
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* Convert :has() selector node to VElementMatcher
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* @param {parser.Selector} selector
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* @returns {VElementMatcher}
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*/
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function pseudoHasSelectorToVElementMatcher(selector) {
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const nodes = cleanSelectorChildren(selector)
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const selectors = selectorToVElementMatcher(nodes)
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const firstNode = nodes[0]
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if (
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firstNode.type === 'combinator' &&
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(firstNode.value === '+' || firstNode.value === '~')
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) {
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// adjacent or sibling
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return buildVElementMatcher(selectors, (element) =>
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getAfterElements(element)
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)
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}
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// descendant or child
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return buildVElementMatcher(selectors, (element) =>
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element.children.filter(isVElement)
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)
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/**
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* @param {VElementMatcher} selectors
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* @param {(element: VElement) => VElement[]} getStartElements
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* @returns {VElementMatcher}
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*/
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function buildVElementMatcher(selectors, getStartElements) {
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return (element) => {
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const elements = [...getStartElements(element)]
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/** @type {VElement|undefined} */
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let curr
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while ((curr = elements.shift())) {
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const el = curr
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if (selectors(el, element)) {
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return true
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}
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elements.push(...el.children.filter(isVElement))
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}
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return false
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}
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}
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}
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|
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/**
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* Parse <nth>
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* @param {parser.Pseudo} pseudoNode
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* @returns {(index: number)=>boolean}
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*/
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function parseNth(pseudoNode) {
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const argumentsText = pseudoNode
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.toString()
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.slice(pseudoNode.value.length)
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.toLowerCase()
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const openParenIndex = argumentsText.indexOf('(')
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const closeParenIndex = argumentsText.lastIndexOf(')')
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if (openParenIndex < 0 || closeParenIndex < 0) {
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throw new SelectorError(
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`Cannot parse An+B micro syntax (:nth-xxx() argument): ${argumentsText}.`
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)
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}
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const argument = argumentsText
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.slice(openParenIndex + 1, closeParenIndex)
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.trim()
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try {
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return nthCheck(argument)
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} catch (e) {
|
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throw new SelectorError(
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`Cannot parse An+B micro syntax (:nth-xxx() argument): '${argument}'.`
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)
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}
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}
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|
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/**
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* Build VElementMatcher for :nth-xxx()
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* @param {(index: number, length: number)=>boolean} testIndex
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* @returns {VElementMatcher}
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*/
|
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function buildPseudoNthVElementMatcher(testIndex) {
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return (element) => {
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const elements = element.parent.children.filter(isVElement)
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return testIndex(elements.indexOf(element), elements.length)
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}
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}
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|
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/**
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* Build VElementMatcher for :nth-xxx-of-type()
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* @param {(index: number, length: number)=>boolean} testIndex
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* @returns {VElementMatcher}
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*/
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function buildPseudoNthOfTypeVElementMatcher(testIndex) {
|
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return (element) => {
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const elements = element.parent.children
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.filter(isVElement)
|
|
.filter((e) => e.rawName === element.rawName)
|
|
return testIndex(elements.indexOf(element), elements.length)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @param {VElement} element
|
|
*/
|
|
function getBeforeElement(element) {
|
|
return getBeforeElements(element).pop() || null
|
|
}
|
|
/**
|
|
* @param {VElement} element
|
|
*/
|
|
function getBeforeElements(element) {
|
|
const parent = element.parent
|
|
const index = parent.children.indexOf(element)
|
|
return parent.children.slice(0, index).filter(isVElement)
|
|
}
|
|
|
|
/**
|
|
* @param {VElement} element
|
|
*/
|
|
function getAfterElements(element) {
|
|
const parent = element.parent
|
|
const index = parent.children.indexOf(element)
|
|
return parent.children.slice(index + 1).filter(isVElement)
|
|
}
|
|
|
|
/**
|
|
* @param {VElementMatcher} a
|
|
* @param {VElementMatcher} b
|
|
* @returns {VElementMatcher}
|
|
*/
|
|
function compound(a, b) {
|
|
return (element, subject) => a(element, subject) && b(element, subject)
|
|
}
|
|
|
|
/**
|
|
* Get attribute value from given element.
|
|
* @param {VElement} element The element node.
|
|
* @param {string} attribute The attribute name.
|
|
*/
|
|
function getAttributeValue(element, attribute) {
|
|
const attr = getAttribute(element, attribute)
|
|
if (attr) {
|
|
return (attr.value && attr.value.value) || ''
|
|
}
|
|
return null
|
|
}
|