biome complexity/noAdjacentSpacesInRegex

• Changes meaning when spaces are significant, e.g., in patterns like '/a b/' where two spaces are required to match.
• Breaks quantifier semantics if spaces are part of a quantified subpattern, e.g., '/(x ){2}/' becomes '/(x ){2}/', altering repetition count.
• Alters behavior in free-spacing mode (/x flag) where literal spaces are ignored and the fix removes meaningful visual spacing.
• Affects regexes relying on exact space counts for parsing, such as fixed-format text matchers like '/\d{3} \d{2}/'.
• Modifies patterns using spaces as delimiters in alternatives, e.g., '/foo | bar/' becomes '/foo | bar/', changing token boundaries.
• Impacts negated character classes containing spaces, e.g., '/[^ ] /' becomes '/[^ ] /', altering what characters are matched.
• Disrupts tab-separated value parsers where literal spaces are significant, e.g., '/\t \t/' becomes '/\t \t/'.
• Removes intentional formatting in complex regexes where spaces improve readability without affecting semantics, but the fix still alters the literal.
• May break code that generates regexes via string concatenation relying on exact space counts from literals, e.g., `new RegExp('/' + pattern + '/')`.
• Interferes with source inspection or debugging where the original literal's space count is logged or compared.

--- orig.js	2026-10-17 16:03:56.217465690 -0400
+++ fixed.js	2026-10-17 16:03:56.506446164 -0400
@@ -1,6 +1,6 @@
 const input = 'a  bc';
 let result;
-if ((/(a)  (bc)/).test(input)) {
+if ((/(a) {2}(bc)/).test(input)) {
   result = RegExp.$1 ?? 'no';
 } else {
   result = undefined;

a

--- orig.js	2026-10-17 16:03:56.669435151 -0400
+++ fixed.js	2026-10-17 16:03:56.955415828 -0400
@@ -1,5 +1,5 @@
 let calls = 0;
 function getStr() { return `str${++calls}`; }
 const str = getStr();
-const re = /foo  ${getStr()}bar/;
+const re = /foo {2}${getStr()}bar/;
 console.log(calls, re.test(str));

1 false

--- orig.js	2026-10-17 16:03:57.127404225 -0400
+++ fixed.js	2026-10-17 16:03:57.400385818 -0400
@@ -1,3 +1,3 @@
 /** spaced */
-const re = /a  /* inner */b  /* end */c/;
+const re = /a {2}/* inner */b {2}/* end */c/;
 console.log(re.source);

--- orig.js	2026-10-17 16:03:57.561374963 -0400
+++ fixed.js	2026-10-17 16:03:57.843355949 -0400
@@ -1,6 +1,6 @@
 "use strict";
 (() => {
-  const re = /\s  \s/;
+  const re = /\s {2}\s/;
   try {
     eval("re.test('  ')");
     console.log('ok');

ok

--- orig.js	2026-10-17 16:03:58.060341327 -0400
+++ fixed.js	2026-10-17 16:03:58.344322218 -0400
@@ -1,3 +1,3 @@
-const re = /^  (\d{3})  -  (\d{2})  -  (\d{4})$/;
+const re = /^ {2}(\d{3}) {2}- {2}(\d{2}) {2}- {2}(\d{4})$/;
 const m = '123-45-6789'.match(re);
 console.log(m ? m[1] + '-' + m[2] + '-' + m[3] : null);

null

--- orig.js	2026-10-17 16:03:58.516310645 -0400
+++ fixed.js	2026-10-17 16:03:58.774293285 -0400
@@ -1,4 +1,4 @@
-function fn(a, b = /x  y/.test('x  y')) {
+function fn(a, b = /x {2}y/.test('x  y')) {
   console.log(arguments.length, b);
 }
 fn(1);

1 true

--- orig.js	2026-10-17 16:03:58.947281645 -0400
+++ fixed.js	2026-10-17 16:03:59.213263777 -0400
@@ -1,2 +1,2 @@
-const re = /a  b  c/;
+const re = /a {2}b {2}c/;
 console.log(re.source.split(' ').length - 1);

4

--- orig.js	2026-10-17 16:04:03.154000070 -0400
+++ fixed.js	2026-10-17 16:04:03.418982422 -0400
@@ -1,7 +1,7 @@
 const obj = {};
 Object.defineProperty(obj, 'pattern', {
-  get() { return /hello  world/.source; },
+  get() { return /hello {2}world/.source; },
   enumerable: true,
   configurable: true
 });
-console.log('Match:', /hello  world/.test(obj.pattern));
+console.log('Match:', /hello {2}world/.test(obj.pattern));

Match: true

--- orig.js	2026-10-17 16:04:03.594970702 -0400
+++ fixed.js	2026-10-17 16:04:03.869952388 -0400
@@ -1,6 +1,6 @@
 function test() {
-  if (false) var r = /a  b/;
-  else var r = /c  d/;
+  if (false) var r = /a {2}b/;
+  else var r = /c {2}d/;
   console.log(r.test('a  b'));
 }
 test();

false

--- orig.js	2026-10-17 16:04:04.042940874 -0400
+++ fixed.js	2026-10-17 16:04:04.305923395 -0400
@@ -1,4 +1,4 @@
-const re = /foo  |  bar/;
+const re = /foo {2}| {2}bar/;
 console.log(re.test('foo'));
 console.log(re.test('  bar'));
 console.log(re.test('foobar'));

false
true
false

--- orig.js	2026-10-17 16:04:04.481911699 -0400
+++ fixed.js	2026-10-17 16:04:04.752893690 -0400
@@ -1,5 +1,5 @@
 {
-  function check(s) { return /test  case/.test(s); }
+  function check(s) { return /test {2}case/.test(s); }
   console.log(check('test  case'));
   console.log(check('testcase'));
 }

true
false

--- orig.js	2026-10-17 16:04:04.928881994 -0400
+++ fixed.js	2026-10-17 16:04:05.208863414 -0400
@@ -1,2 +1,2 @@
 let x = 1
-(/space  /).test('space  ') ? console.log('matched') : console.log('not')
+(/space {2}/).test('space  ') ? console.log('matched') : console.log('not')

--- orig.js	2026-10-17 16:04:05.371852604 -0400
+++ fixed.js	2026-10-17 16:04:05.641834698 -0400
@@ -1,5 +1,5 @@
 try {
-  const re = /fail  here/;
+  const re = /fail {2}here/;
   throw new Error('deliberate');
 } catch (e) {
   console.log('Caught:', e.constructor.name, e.message);

Caught: Error deliberate

--- orig.js	2026-10-17 16:04:05.805823822 -0400
+++ fixed.js	2026-10-17 16:04:06.068806389 -0400
@@ -1,4 +1,4 @@
 const line = 'a\tb\tc';
-const re = /\t  \t/;
+const re = /\t {2}\t/;
 console.log('TSV match:', re.test(line));
 console.log('Expected fields:', line.split('\t'));

TSV match: false
Expected fields: [ 'a', 'b', 'c' ]

--- orig.js	2026-10-17 16:04:06.229795734 -0400
+++ fixed.js	2026-10-17 16:04:06.504777534 -0400
@@ -1,4 +1,4 @@
-const re = /💩  💩/gu;
+const re = /💩 {2}💩/gu;
 console.log('First:', re.test('💩  💩'));
 console.log('lastIndex after:', re.lastIndex);
 re.lastIndex = 0;

First: true
lastIndex after: 6
Second: false