/** * Copyright 2023 Google Inc. All rights reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import {Token, tokenize, TOKENS, stringify} from 'parsel-js'; export type CSSSelector = string; export interface PPseudoSelector { name: string; value: string; } export const enum PCombinator { Descendent = '>>>', Child = '>>>>', } export type CompoundPSelector = Array; export type ComplexPSelector = Array; export type ComplexPSelectorList = ComplexPSelector[]; TOKENS['combinator'] = /\s*(>>>>?|[\s>+~])\s*/g; const ESCAPE_REGEXP = /\\[\s\S]/g; const unquote = (text: string): string => { if (text.length <= 1) { return text; } if ((text[0] === '"' || text[0] === "'") && text.endsWith(text[0])) { text = text.slice(1, -1); } return text.replace(ESCAPE_REGEXP, match => { return match[1] as string; }); }; export function parsePSelectors( selector: string ): [selector: ComplexPSelectorList, isPureCSS: boolean] { let isPureCSS = true; const tokens = tokenize(selector); if (tokens.length === 0) { return [[], isPureCSS]; } let compoundSelector: CompoundPSelector = []; let complexSelector: ComplexPSelector = [compoundSelector]; const selectors: ComplexPSelectorList = [complexSelector]; const storage: Token[] = []; for (const token of tokens) { switch (token.type) { case 'combinator': switch (token.content) { case PCombinator.Descendent: isPureCSS = false; if (storage.length) { compoundSelector.push(stringify(storage)); storage.splice(0); } compoundSelector = []; complexSelector.push(PCombinator.Descendent); complexSelector.push(compoundSelector); continue; case PCombinator.Child: isPureCSS = false; if (storage.length) { compoundSelector.push(stringify(storage)); storage.splice(0); } compoundSelector = []; complexSelector.push(PCombinator.Child); complexSelector.push(compoundSelector); continue; } break; case 'pseudo-element': if (!token.name.startsWith('-p-')) { break; } isPureCSS = false; if (storage.length) { compoundSelector.push(stringify(storage)); storage.splice(0); } compoundSelector.push({ name: token.name.slice(3), value: unquote(token.argument ?? ''), }); continue; case 'comma': if (storage.length) { compoundSelector.push(stringify(storage)); storage.splice(0); } compoundSelector = []; complexSelector = [compoundSelector]; selectors.push(complexSelector); continue; } storage.push(token); } if (storage.length) { compoundSelector.push(stringify(storage)); } return [selectors, isPureCSS]; }