Enable regexp/no-unused-capturing-group rule

.eslintrc.js

@@ -104,6 +104,7 @@ module.exports = {
         allows: ["dotAll"],
       },
     ],
+    "regexp/no-unused-capturing-group": "error",
     "regexp/no-useless-flag": [
       "error",
       {

src/language-css/clean.js

@@ -37,7 +37,7 @@ function clean(ast, newObj, parent) {
       delete newObj.text;
 
       // standalone pragma
-      if (/^\*\s*@(format|prettier)\s*$/.test(ast.text)) {
+      if (/^\*\s*@(?:format|prettier)\s*$/.test(ast.text)) {
         return null;
       }
     }

src/language-css/parser-postcss.js

@@ -515,7 +515,7 @@ function parseNestedCSS(node, options) {
       }
 
       if (name === "at-root") {
-        if (/^\(\s*(without|with)\s*:.+\)$/s.test(params)) {
+        if (/^\(\s*(?:without|with)\s*:.+\)$/s.test(params)) {
           node.params = parseValue(params, options);
         } else {
           node.selector = parseSelector(params);

src/language-css/utils.js

@@ -89,7 +89,7 @@ function hasStringOrFunction(groupList) {
 
 function isSCSS(parser, text) {
   const hasExplicitParserChoice = parser === "less" || parser === "scss";
-  const IS_POSSIBLY_SCSS = /(\w\s*:\s*[^:}]+|#){|@import[^\n]+(?:url|,)/;
+  const IS_POSSIBLY_SCSS = /(?:\w\s*:\s*[^:}]+|#){|@import[^\n]+(?:url|,)/;
   return hasExplicitParserChoice
     ? parser === "scss"
     : IS_POSSIBLY_SCSS.test(text);

src/language-graphql/pragma.js

@@ -1,7 +1,7 @@
 "use strict";
 
 function hasPragma(text) {
-  return /^\s*#[^\S\n]*@(format|prettier)\s*(\n|$)/.test(text);
+  return /^\s*#[^\S\n]*@(?:format|prettier)\s*(?:\n|$)/.test(text);
 }
 
 function insertPragma(text) {

src/language-html/pragma.js

@@ -1,7 +1,7 @@
 "use strict";
 
 function hasPragma(text) {
-  return /^\s*<!--\s*@(format|prettier)\s*-->/.test(text);
+  return /^\s*<!--\s*@(?:format|prettier)\s*-->/.test(text);
 }
 
 function insertPragma(text) {

src/language-html/syntax-vue.js

@@ -73,7 +73,7 @@ function printVueBindings(value, textToDoc) {
 function isVueEventBindingExpression(eventBindingValue) {
   // https://github.com/vuejs/vue/blob/v2.5.17/src/compiler/codegen/events.js#L3-L4
   // arrow function or anonymous function
-  const fnExpRE = /^([\w$]+|\([^)]*?\))\s*=>|^function\s*\(/;
+  const fnExpRE = /^(?:[\w$]+|\([^)]*?\))\s*=>|^function\s*\(/;
   // simple member expression chain (a, a.b, a['b'], a["b"], a[0], a[b])
   const simplePathRE =
     /^[$A-Z_a-z][\w$]*(?:\.[$A-Z_a-z][\w$]*|\['[^']*?']|\["[^"]*?"]|\[\d+]|\[[$A-Z_a-z][\w$]*])*$/;

src/language-js/parse/typescript.js

@@ -63,9 +63,9 @@ function parse(text, parsers, opts) {
 function isProbablyJsx(text) {
   return new RegExp(
     [
-      "(^[^\"'`]*</)", // Contains "</" when probably not in a string
+      "(?:^[^\"'`]*</)", // Contains "</" when probably not in a string
       "|",
-      "(^[^/]{2}.*/>)", // Contains "/>" on line not starting with "//"
+      "(?:^[^/]{2}.*/>)", // Contains "/>" on line not starting with "//"
     ].join(""),
     "m"
   ).test(text);

src/language-js/print/angular.js

@@ -54,7 +54,7 @@ function printAngular(path, options, print) {
         "body"
       );
     case "NGMicrosyntaxKey":
-      return /^[$_a-z][\w$]*(-[$_a-z][\w$])*$/i.test(node.name)
+      return /^[$_a-z][\w$]*(?:-[$_a-z][\w$])*$/i.test(node.name)
         ? node.name
         : JSON.stringify(node.name);
     case "NGMicrosyntaxExpression":

src/language-js/print/typescript.js

@@ -467,7 +467,7 @@ function printTypescript(path, options, print) {
         if (!isGlobalDeclaration) {
           parts.push(
             isExternalModule ||
-              /(^|\s)module(\s|$)/.test(textBetweenNodeAndItsId)
+              /(?:^|\s)module(?:\s|$)/.test(textBetweenNodeAndItsId)
               ? "module "
               : "namespace "
           );

src/language-js/utils.js

@@ -480,7 +480,7 @@ function isSimpleType(node) {
   return false;
 }
 
-const unitTestRe = /^(skip|[fx]?(it|describe|test))$/;
+const unitTestRe = /^(?:skip|[fx]?(?:it|describe|test))$/;
 
 /**
  * @param {{callee: MemberExpression | OptionalMemberExpression}} node
@@ -502,7 +502,7 @@ function isSkipOrOnlyBlock(node) {
  * @returns {boolean}
  */
 function isUnitTestSetUp(node) {
-  const unitTestSetUpRe = /^(before|after)(Each|All)$/;
+  const unitTestSetUpRe = /^(?:before|after)(?:Each|All)$/;
   return (
     node.callee.type === "Identifier" &&
     unitTestSetUpRe.test(node.callee.name) &&
@@ -722,7 +722,7 @@ function isStringPropSafeToUnquote(node, options) {
 
 // Matches “simple” numbers like `123` and `2.5` but not `1_000`, `1e+100` or `0b10`.
 function isSimpleNumber(numberString) {
-  return /^(\d+|\d+\.\d+)$/.test(numberString);
+  return /^(?:\d+|\d+\.\d+)$/.test(numberString);
 }
 
 /**
@@ -741,7 +741,7 @@ function isJestEachTemplateLiteral(node, parentNode) {
    *
    * Ref: https://github.com/facebook/jest/pull/6102
    */
-  const jestEachTriggerRegex = /^[fx]?(describe|it|test)$/;
+  const jestEachTriggerRegex = /^[fx]?(?:describe|it|test)$/;
   return (
     parentNode.type === "TaggedTemplateExpression" &&
     parentNode.quasi === node &&

src/language-markdown/print-preprocess.js

@@ -134,7 +134,7 @@ function transformIndentedCodeblockAndMarkItsParentList(ast, options) {
   return mapAst(ast, (node, index, parentStack) => {
     if (node.type === "code") {
       // the first char may point to `\n`, e.g. `\n\t\tbar`, just ignore it
-      const isIndented = /^\n?( {4,}|\t)/.test(
+      const isIndented = /^\n?(?: {4,}|\t)/.test(
         options.originalText.slice(
           node.position.start.offset,
           node.position.end.offset

src/language-markdown/printer-markdown.js

@@ -142,7 +142,7 @@ function genericPrint(path, options, print) {
 
       const proseWrap =
         // leading char that may cause different syntax
-        nextNode && /^>|^([*+-]|#{1,6}|\d+[).])$/.test(nextNode.value)
+        nextNode && /^>|^(?:[*+-]|#{1,6}|\d+[).])$/.test(nextNode.value)
           ? "never"
           : options.proseWrap;
 

src/language-yaml/pragma.js

@@ -1,11 +1,11 @@
 "use strict";
 
 function isPragma(text) {
-  return /^\s*@(prettier|format)\s*$/.test(text);
+  return /^\s*@(?:prettier|format)\s*$/.test(text);
 }
 
 function hasPragma(text) {
-  return /^\s*#[^\S\n]*@(prettier|format)\s*?(\n|$)/.test(text);
+  return /^\s*#[^\S\n]*@(?:prettier|format)\s*?(?:\n|$)/.test(text);
 }
 
 function insertPragma(text) {

src/language-yaml/printer-yaml.js

@@ -387,7 +387,7 @@ function shouldPrintDocumentHeadEndMarker(
      * preserve the first document head end marker
      */
     (root.children[0] === document &&
-      /---(\s|$)/.test(
+      /---(?:\s|$)/.test(
         options.originalText.slice(locStart(document), locStart(document) + 4)
       )) ||
     /**