"use strict" const findAtRuleContext = require("../../utils/findAtRuleContext") const isKeyframeRule = require("../../utils/isKeyframeRule") const nodeContextLookup = require("../../utils/nodeContextLookup") const report = require("../../utils/report") const ruleMessages = require("../../utils/ruleMessages") const validateOptions = require("../../utils/validateOptions") const _ = require("lodash") const normalizeSelector = require("normalize-selector") const resolvedNestedSelector = require("postcss-resolve-nested-selector") const ruleName = "no-duplicate-selectors" const messages = ruleMessages(ruleName, { rejected: selector => `Unexpected duplicate selector "${selector}"`, }) const rule = function (actual) { return (root, result) => { const validOptions = validateOptions(result, ruleName, { actual }) if (!validOptions) { return } // The top level of this map will be rule sources. // Each source maps to another map, which maps rule parents to a set of selectors. // This ensures that selectors are only checked against selectors // from other rules that share the same parent and the same source. const selectorContextLookup = nodeContextLookup() root.walkRules(rule => { if (isKeyframeRule(rule)) { return } const contextSelectorSet = selectorContextLookup.getContext(rule, findAtRuleContext(rule)) const resolvedSelectors = rule.selectors.reduce((result, selector) => { return _.union(result, resolvedNestedSelector(selector, rule)) }, []) const normalizedSelectorList = resolvedSelectors.map(normalizeSelector) // Complain if the same selector list occurs twice // Sort the selectors list so that the order of the constituents // doesn't matter const sortedSelectorList = normalizedSelectorList.slice().sort().join(",") if (contextSelectorSet.has(sortedSelectorList)) { // If the selector isn't nested we can use its raw value; otherwise, // we have to approximate something for the message -- which is close enough const isNestedSelector = resolvedSelectors.join(",") !== rule.selectors.join(",") const selectorForMessage = isNestedSelector ? resolvedSelectors.join(", ") : rule.selector return report({ result, ruleName, node: rule, message: messages.rejected(selectorForMessage), }) } // We're treating the Map created by nodeContextLookup as a Set contextSelectorSet.set(sortedSelectorList, null) // Or complain if one selector list contains the same selector more than one rule.selectors.forEach((selector, i) => { if (_.includes(normalizedSelectorList.slice(0, i), normalizeSelector(selector))) { report({ result, ruleName, node: rule, message: messages.rejected(selector), }) } }) }) } } rule.ruleName = ruleName rule.messages = messages module.exports = rule