feat: Fixer for missing unicode flag in no-misleading-character-class

lib/rules/no-misleading-character-class.js

@@ -108,14 +108,19 @@ module.exports = {
             url: "https://eslint.org/docs/rules/no-misleading-character-class"
         },
 
+        hasSuggestions: true,
+
         schema: [],
 
+        fixable: "whitespace",
+
         messages: {
             surrogatePairWithoutUFlag: "Unexpected surrogate pair in character class. Use 'u' flag.",
             combiningClass: "Unexpected combined character in character class.",
             emojiModifier: "Unexpected modified Emoji in character class.",
             regionalIndicatorSymbol: "Unexpected national flag in character class.",
-            zwj: "Unexpected joined character sequence in character class."
+            zwj: "Unexpected joined character sequence in character class.",
+            suggestUnicodeFlag: "Add unicode 'u' flag to regex."
         }
     },
     create(context) {
@@ -126,17 +131,10 @@ module.exports = {
          * @param {Node} node The node to report.
          * @param {string} pattern The regular expression pattern to verify.
          * @param {string} flags The flags of the regular expression.
+         * @param {Function} unicodeFixer Fixer for missing "u" flag.
          * @returns {void}
          */
-        function verify(node, pattern, flags) {
-            const has = {
-                surrogatePairWithoutUFlag: false,
-                combiningClass: false,
-                variationSelector: false,
-                emojiModifier: false,
-                regionalIndicatorSymbol: false,
-                zwj: false
-            };
+        function verify(node, pattern, flags, unicodeFixer) {
             let patternNode;
 
             try {
@@ -152,26 +150,41 @@ module.exports = {
                 return;
             }
 
+            const foundKinds = new Set();
+
             visitRegExpAST(patternNode, {
                 onCharacterClassEnter(ccNode) {
                     for (const chars of iterateCharacterSequence(ccNode.elements)) {
                         for (const kind of kinds) {
-                            has[kind] = has[kind] || hasCharacterSequence[kind](chars);
+                            if (hasCharacterSequence[kind](chars)) {
+                                foundKinds.add(kind);
+                            }
                         }
                     }
                 }
             });
 
-            for (const kind of kinds) {
-                if (has[kind]) {
-                    context.report({ node, messageId: kind });
+            for (const kind of foundKinds) {
+                let suggest;
+
+                if (kind === "surrogatePairWithoutUFlag") {
+                    suggest = [{
+                        messageId: "suggestUnicodeFlag",
+                        fix: unicodeFixer
+                    }];
                 }
+
+                context.report({
+                    node,
+                    messageId: kind,
+                    suggest
+                });
             }
         }
 
         return {
             "Literal[regex]"(node) {
-                verify(node, node.regex.pattern, node.regex.flags);
+                verify(node, node.regex.pattern, node.regex.flags, fixer => fixer.insertTextAfter(node, "u"));
             },
             "Program"() {
                 const scope = context.getScope();
@@ -190,7 +203,19 @@ module.exports = {
                     const flags = getStringIfConstant(flagsNode, scope);
 
                     if (typeof pattern === "string") {
-                        verify(node, pattern, flags || "");
+                        verify(node, pattern, flags || "", fixer => {
+                            if (node.arguments.length === 1) {
+                                return fixer.insertTextAfterRange(patternNode.range, ', "u"');
+                            }
+
+                            if (flagsNode.type === "Literal" || flagsNode.type === "TemplateLiteral") {
+                                const range = [flagsNode.range[0], flagsNode.range[1] - 1];
+
+                                return fixer.insertTextAfterRange(range, "u");
+                            }
+
+                            return null;
+                        });
                     }
                 }
             }