feat: prefer-named-capture-group add suggestions (#16544)

* feat: [prefer-named-capture-group] add suggestions

* Add test for proper parenthesis matching

* fix: only suggest when there are no \s

* More granular checking of suggestion viability

* Feedback: return null in more cases, no more indexOf, suggestions: null

* Account for existing temps

lib/rules/prefer-named-capture-group.js

@@ -23,6 +23,61 @@ const regexpp = require("regexpp");
 
 const parser = new regexpp.RegExpParser();
 
+/**
+ * Creates fixer suggestions for the regex, if statically determinable.
+ * @param {number} groupStart Starting index of the regex group.
+ * @param {string} pattern The regular expression pattern to be checked.
+ * @param {string} rawText Source text of the regexNode.
+ * @param {ASTNode} regexNode AST node which contains the regular expression.
+ * @returns {Array<SuggestionResult>} Fixer suggestions for the regex, if statically determinable.
+ */
+function suggestIfPossible(groupStart, pattern, rawText, regexNode) {
+    switch (regexNode.type) {
+        case "Literal":
+            if (typeof regexNode.value === "string" && rawText.includes("\\")) {
+                return null;
+            }
+            break;
+        case "TemplateLiteral":
+            if (regexNode.expressions.length || rawText.slice(1, -1) !== pattern) {
+                return null;
+            }
+            break;
+        default:
+            return null;
+    }
+
+    const start = regexNode.range[0] + groupStart + 2;
+
+    return [
+        {
+            fix(fixer) {
+                const existingTemps = pattern.match(/temp\d+/gu) || [];
+                const highestTempCount = existingTemps.reduce(
+                    (previous, next) =>
+                        Math.max(previous, Number(next.slice("temp".length))),
+                    0
+                );
+
+                return fixer.insertTextBeforeRange(
+                    [start, start],
+                    `?<temp${highestTempCount + 1}>`
+                );
+            },
+            messageId: "addGroupName"
+        },
+        {
+            fix(fixer) {
+                return fixer.insertTextBeforeRange(
+                    [start, start],
+                    "?:"
+                );
+            },
+            messageId: "addNonCapture"
+        }
+    ];
+}
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -38,23 +93,29 @@ module.exports = {
             url: "https://eslint.org/docs/rules/prefer-named-capture-group"
         },
 
+        hasSuggestions: true,
+
         schema: [],
 
         messages: {
+            addGroupName: "Add name to capture group.",
+            addNonCapture: "Convert group to non-capturing.",
             required: "Capture group '{{group}}' should be converted to a named or non-capturing group."
         }
     },
 
     create(context) {
+        const sourceCode = context.getSourceCode();
 
         /**
          * Function to check regular expression.
-         * @param {string} pattern The regular expression pattern to be check.
-         * @param {ASTNode} node AST node which contains regular expression.
+         * @param {string} pattern The regular expression pattern to be checked.
+         * @param {ASTNode} node AST node which contains the regular expression or a call/new expression.
+         * @param {ASTNode} regexNode AST node which contains the regular expression.
          * @param {boolean} uFlag Flag indicates whether unicode mode is enabled or not.
          * @returns {void}
          */
-        function checkRegex(pattern, node, uFlag) {
+        function checkRegex(pattern, node, regexNode, uFlag) {
             let ast;
 
             try {
@@ -68,12 +129,16 @@ module.exports = {
             regexpp.visitRegExpAST(ast, {
                 onCapturingGroupEnter(group) {
                     if (!group.name) {
+                        const rawText = sourceCode.getText(regexNode);
+                        const suggest = suggestIfPossible(group.start, pattern, rawText, regexNode);
+
                         context.report({
                             node,
                             messageId: "required",
                             data: {
                                 group: group.raw
-                            }
+                            },
+                            suggest
                         });
                     }
                 }
@@ -83,7 +148,7 @@ module.exports = {
         return {
             Literal(node) {
                 if (node.regex) {
-                    checkRegex(node.regex.pattern, node, node.regex.flags.includes("u"));
+                    checkRegex(node.regex.pattern, node, node, node.regex.flags.includes("u"));
                 }
             },
             Program() {
@@ -101,7 +166,7 @@ module.exports = {
                     const flags = getStringIfConstant(node.arguments[1]);
 
                     if (regex) {
-                        checkRegex(regex, node, flags && flags.includes("u"));
+                        checkRegex(regex, node, node.arguments[0], flags && flags.includes("u"));
                     }
                 }
             }