Normalize x-model boolean parsing for case and whitespace

packages/alpinejs/src/utils/bind.js

@@ -135,11 +135,23 @@ function checkedAttrLooseCompare(valueA, valueB) {
 }
 
 export function safeParseBoolean(rawValue) {
-    if ([1, '1', 'true', 'on', 'yes', true].includes(rawValue)) {
+    if ([1, true].includes(rawValue)) {
         return true
     }
 
-    if ([0, '0', 'false', 'off', 'no', false].includes(rawValue)) {
+    if ([0, false].includes(rawValue)) {
+        return false
+    }
+
+    let normalizedString = typeof rawValue === 'string'
+        ? rawValue.trim().toLowerCase()
+        : rawValue
+
+    if (['1', 'true', 'on', 'yes'].includes(normalizedString)) {
+        return true
+    }
+
+    if (['0', 'false', 'off', 'no'].includes(normalizedString)) {
         return false
     }
 

packages/docs/src/en/directives/model.md

@@ -385,7 +385,7 @@ By default, any data stored in a property via `x-model` is stored as a string. T
 <a name="boolean"></a>
 ### `.boolean`
 
-By default, any data stored in a property via `x-model` is stored as a string. To force Alpine to store the value as a JavaScript boolean, add the `.boolean` modifier. Both integers (1/0) and strings (true/false) are valid boolean values.
+By default, any data stored in a property via `x-model` is stored as a string. To force Alpine to store the value as a JavaScript boolean, add the `.boolean` modifier. Both integers (1/0) and strings (true/false) are valid boolean values. Matching is case-insensitive and ignores surrounding whitespace.
 
 ```alpine
 <select x-model.boolean="isActive">

tests/vitest/bind.spec.js

@@ -0,0 +1,28 @@
+// @vitest-environment jsdom
+
+import { beforeAll, describe, expect, it } from 'vitest'
+import Alpine from '../../packages/alpinejs/src/index.js'
+
+let safeParseBoolean
+
+beforeAll(async () => {
+    Alpine.start()
+    safeParseBoolean = (await import('../../packages/alpinejs/src/utils/bind.js')).safeParseBoolean
+})
+
+describe('safeParseBoolean', () => {
+    it('handles mixed case and surrounding whitespace for known values', () => {
+        expect(safeParseBoolean(' TRUE ')).toBe(true)
+        expect(safeParseBoolean(' yes ')).toBe(true)
+        expect(safeParseBoolean(' 1 ')).toBe(true)
+
+        expect(safeParseBoolean(' FALSE ')).toBe(false)
+        expect(safeParseBoolean(' off ')).toBe(false)
+        expect(safeParseBoolean(' 0 ')).toBe(false)
+    })
+
+    it('keeps legacy fallback behavior for unknown values', () => {
+        expect(safeParseBoolean('unknown')).toBe(true)
+        expect(safeParseBoolean('')).toBe(null)
+    })
+})