--- /dev/null
+"use strict";
+
+const _ = require("lodash");
+const isStandardSyntaxRule = require("../../utils/isStandardSyntaxRule");
+const keywordSets = require("../../reference/keywordSets");
+const report = require("../../utils/report");
+const ruleMessages = require("../../utils/ruleMessages");
+const styleSearch = require("style-search");
+const validateOptions = require("../../utils/validateOptions");
+
+const ruleName = "selector-pseudo-element-colon-notation";
+
+const messages = ruleMessages(ruleName, {
+ expected: q => `Expected ${q} colon pseudo-element notation`
+});
+
+const rule = function(expectation) {
+ return (root, result) => {
+ const validOptions = validateOptions(result, ruleName, {
+ actual: expectation,
+ possible: ["single", "double"]
+ });
+ if (!validOptions) {
+ return;
+ }
+
+ root.walkRules(rule => {
+ if (!isStandardSyntaxRule(rule)) {
+ return;
+ }
+ const selector = rule.selector;
+
+ // get out early if no pseudo elements or classes
+ if (selector.indexOf(":") === -1) {
+ return;
+ }
+
+ // match only level 1 and 2 pseudo elements
+ const pseudoElementsWithColons = _.toArray(
+ keywordSets.levelOneAndTwoPseudoElements
+ ).map(x => `:${x}`);
+ styleSearch(
+ { source: selector.toLowerCase(), target: pseudoElementsWithColons },
+ match => {
+ const prevCharIsColon = selector[match.startIndex - 1] === ":";
+
+ if (expectation === "single" && !prevCharIsColon) {
+ return;
+ }
+ if (expectation === "double" && prevCharIsColon) {
+ return;
+ }
+
+ report({
+ message: messages.expected(expectation),
+ node: rule,
+ index: match.startIndex,
+ result,
+ ruleName
+ });
+ }
+ );
+ });
+ };
+};
+
+rule.ruleName = ruleName;
+rule.messages = messages;
+module.exports = rule;