Add components

slider/node_modules/eslint/lib/rules/no-empty-character-class.js

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+/**
+ * @fileoverview Rule to flag the use of empty character classes in regular expressions
+ * @author Ian Christian Myers
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const { RegExpParser, visitRegExpAST } = require("@eslint-community/regexpp");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const parser = new RegExpParser();
+const QUICK_TEST_REGEX = /\[\]/u;
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+/** @type {import('../types').Rule.RuleModule} */
+module.exports = {
+	meta: {
+		type: "problem",
+
+		docs: {
+			description:
+				"Disallow empty character classes in regular expressions",
+			recommended: true,
+			url: "https://eslint.org/docs/latest/rules/no-empty-character-class",
+		},
+
+		schema: [],
+
+		messages: {
+			unexpected: "Empty class.",
+		},
+	},
+
+	create(context) {
+		return {
+			"Literal[regex]"(node) {
+				const { pattern, flags } = node.regex;
+
+				if (!QUICK_TEST_REGEX.test(pattern)) {
+					return;
+				}
+
+				let regExpAST;
+
+				try {
+					regExpAST = parser.parsePattern(
+						pattern,
+						0,
+						pattern.length,
+						{
+							unicode: flags.includes("u"),
+							unicodeSets: flags.includes("v"),
+						},
+					);
+				} catch {
+					// Ignore regular expressions that regexpp cannot parse
+					return;
+				}
+
+				visitRegExpAST(regExpAST, {
+					onCharacterClassEnter(characterClass) {
+						if (
+							!characterClass.negate &&
+							characterClass.elements.length === 0
+						) {
+							context.report({ node, messageId: "unexpected" });
+						}
+					},
+				});
+			},
+		};
+	},
+};