From 89219d906f3d50a2a7072f410e080c9e7ca939ec Mon Sep 17 00:00:00 2001
From: zan mlakar <z4n.mlakar@gmail.com>
Date: Wed, 7 Oct 2026 19:41:23 +0200
Subject: [PATCH] fix: support single-dash boolean negation without short
 option groups

---
 lib/yargs-parser.ts   |  4 +++-
 test/yargs-parser.mjs | 56 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/lib/yargs-parser.ts b/lib/yargs-parser.ts
index 48a2d0f2..15f77bda 100644
--- a/lib/yargs-parser.ts
+++ b/lib/yargs-parser.ts
@@ -109,7 +109,9 @@ export class YargsParser {
       keys: []
     }
     const negative = /^-([0-9]+(\.[0-9]+)?|\.[0-9]+)$/
-    const negatedBoolean = new RegExp('^--' + configuration['negation-prefix'] + '(.+)')
+    const negatedBoolean = new RegExp(
+      (configuration['short-option-groups'] ? '^--' : '^--?') + configuration['negation-prefix'] + '(.+)'
+    )
 
     ;([] as ArrayOption[]).concat(opts.array || []).filter(Boolean).forEach(function (opt) {
       const key = typeof opt === 'object' ? opt.key : opt
diff --git a/test/yargs-parser.mjs b/test/yargs-parser.mjs
index 4c692375..76b0df8e 100644
--- a/test/yargs-parser.mjs
+++ b/test/yargs-parser.mjs
@@ -2530,6 +2530,62 @@ describe('yargs-parser', function () {
     })
 
     describe('boolean negation', function () {
+      it('negates single-dash long options when short option groups are disabled', function () {
+        const parsed = parser(['-no-window'], {
+          configuration: { 'short-option-groups': false }
+        })
+
+        expect(parsed.window).to.equal(false)
+        expect(parsed['no-window']).to.equal(undefined)
+      })
+
+      it('uses the custom negation prefix for single-dash long options', function () {
+        const parsed = parser(['-without-window'], {
+          configuration: {
+            'short-option-groups': false,
+            'negation-prefix': 'without-'
+          }
+        })
+
+        expect(parsed.window).to.equal(false)
+      })
+
+      it('recognizes known single-dash negated options with aliases and arrays', function () {
+        const parsed = parser(['-no-window', '-no-unknown'], {
+          boolean: ['window'],
+          array: ['window'],
+          alias: { window: 'w' },
+          configuration: {
+            'short-option-groups': false,
+            'unknown-options-as-args': true
+          }
+        })
+
+        expect(parsed.window).to.deep.equal([false])
+        expect(parsed.w).to.deep.equal([false])
+        expect(parsed._).to.deep.equal(['-no-unknown'])
+      })
+
+      it('respects disabled boolean negation for single-dash long options', function () {
+        const parsed = parser(['-no-window'], {
+          configuration: {
+            'short-option-groups': false,
+            'boolean-negation': false
+          }
+        })
+
+        expect(parsed['no-window']).to.equal(true)
+        expect(parsed.window).to.equal(undefined)
+      })
+
+      it('preserves short option groups for arguments resembling negated options', function () {
+        const parsed = parser(['-no-x'])
+
+        expect(parsed.n).to.equal(true)
+        expect(parsed.o).to.equal('-x')
+        expect(parsed.x).to.equal(undefined)
+      })
+
       it('does not negate arguments prefixed with --no-', function () {
         const parsed = parser(['--no-dice'], {
           configuration: {