Add option for capturing groups to regexp/optimal-quantifier-concatenation (#452)

* Add option for capturing groups to `regexp/optimal-quantifier-concatenation`

* Fixed tests

* FIxed typo

* Removed extra empty line

Author: RunDevelopment

docs/rules/optimal-quantifier-concatenation.md

@@ -43,7 +43,36 @@ var foo = /\w+(?:(a)|b)*/;
 
 ## :wrench: Options
 
-Nothing.
+```json5
+{
+  "regexp/optimal-quantifier-concatenation": [
+    "error",
+    {
+        "capturingGroups": "report"
+    }
+  ]
+}
+```
+
+### `capturingGroups`
+
+The type of concatenation this rule reports might be intentional around capturing groups. This option allows you turn of false unfixable reports around capturing groups.
+
+- `capturingGroups: "report"` (_default_)
+
+  Concatenations around quantifiers will be reported.
+
+- `capturingGroups: "ignore"`
+
+  Concatenations around quantifiers will not be reported.
+
+  If this option is used, it is recommend to have the [regexp/no-super-linear-backtracking] rule enabled to protect against ReDoS.
+
+## :books: Further reading
+
+- [regexp/no-super-linear-backtracking]
+
+[regexp/no-super-linear-backtracking]: ./no-super-linear-backtracking.md
 
 ## :rocket: Version
 

lib/rules/optimal-quantifier-concatenation.ts

@@ -499,6 +499,11 @@ function getLoc(
     })
 }
 
+const enum CapturingGroupReporting {
+    ignore = "ignore",
+    report = "report",
+}
+
 export default createRule("optimal-quantifier-concatenation", {
     meta: {
         docs: {
@@ -508,7 +513,17 @@ export default createRule("optimal-quantifier-concatenation", {
             recommended: true,
         },
         fixable: "code",
-        schema: [],
+        schema: [
+            {
+                type: "object",
+                properties: {
+                    capturingGroups: {
+                        enum: ["ignore", "report"],
+                    },
+                },
+                additionalProperties: false,
+            },
+        ],
         messages: {
             combine:
                 "{{left}} and {{right}} can be combined into one quantifier {{fix}}.{{cap}}",
@@ -526,6 +541,10 @@ export default createRule("optimal-quantifier-concatenation", {
         type: "suggestion",
     },
     create(context) {
+        const cgReporting: CapturingGroupReporting =
+            context.options[0]?.capturingGroups ??
+            CapturingGroupReporting.report
+
         /**
          * Creates a visitor
          */
@@ -548,6 +567,12 @@ export default createRule("optimal-quantifier-concatenation", {
 
                         const involvesCapturingGroup =
                             hasCapturingGroup(left) || hasCapturingGroup(right)
+                        if (
+                            involvesCapturingGroup &&
+                            cgReporting === CapturingGroupReporting.ignore
+                        ) {
+                            continue
+                        }
 
                         const cap = involvesCapturingGroup
                             ? " This cannot be fixed automatically because it might change or remove a capturing group."

tests/lib/rules/optimal-quantifier-concatenation.ts

@@ -19,6 +19,10 @@ tester.run("optimal-quantifier-concatenation", rule as any, {
         String.raw`/\d+(?:\w+|-\d+)/`,
         String.raw`/aa?/`,
         String.raw`/\w?\w/`,
+        {
+            code: String.raw`/(\d)\d+/`,
+            options: [{ capturingGroups: "ignore" }],
+        },
     ],
     invalid: [
         {