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79 lines
2.4 KiB
JavaScript
79 lines
2.4 KiB
JavaScript
import { AttributeAction, SelectorType } from "css-what";
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const procedure = new Map([
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[SelectorType.Universal, 50],
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[SelectorType.Tag, 30],
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[SelectorType.Attribute, 1],
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[SelectorType.Pseudo, 0],
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]);
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export function isTraversal(token) {
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return !procedure.has(token.type);
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}
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const attributes = new Map([
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[AttributeAction.Exists, 10],
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[AttributeAction.Equals, 8],
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[AttributeAction.Not, 7],
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[AttributeAction.Start, 6],
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[AttributeAction.End, 6],
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[AttributeAction.Any, 5],
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]);
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/**
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* Sort the parts of the passed selector,
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* as there is potential for optimization
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* (some types of selectors are faster than others)
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*
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* @param arr Selector to sort
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*/
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export default function sortByProcedure(arr) {
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const procs = arr.map(getProcedure);
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for (let i = 1; i < arr.length; i++) {
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const procNew = procs[i];
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if (procNew < 0)
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continue;
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for (let j = i - 1; j >= 0 && procNew < procs[j]; j--) {
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const token = arr[j + 1];
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arr[j + 1] = arr[j];
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arr[j] = token;
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procs[j + 1] = procs[j];
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procs[j] = procNew;
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}
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}
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}
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function getProcedure(token) {
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var _a, _b;
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let proc = (_a = procedure.get(token.type)) !== null && _a !== void 0 ? _a : -1;
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if (token.type === SelectorType.Attribute) {
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proc = (_b = attributes.get(token.action)) !== null && _b !== void 0 ? _b : 4;
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if (token.action === AttributeAction.Equals && token.name === "id") {
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// Prefer ID selectors (eg. #ID)
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proc = 9;
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}
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if (token.ignoreCase) {
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/*
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* IgnoreCase adds some overhead, prefer "normal" token
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* this is a binary operation, to ensure it's still an int
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*/
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proc >>= 1;
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}
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}
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else if (token.type === SelectorType.Pseudo) {
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if (!token.data) {
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proc = 3;
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}
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else if (token.name === "has" || token.name === "contains") {
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proc = 0; // Expensive in any case
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}
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else if (Array.isArray(token.data)) {
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// Eg. :matches, :not
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proc = Math.min(...token.data.map((d) => Math.min(...d.map(getProcedure))));
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// If we have traversals, try to avoid executing this selector
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if (proc < 0) {
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proc = 0;
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}
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}
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else {
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proc = 2;
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}
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}
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return proc;
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}
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//# sourceMappingURL=sort.js.map
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