refactor: clean class (#26879)

web/src/lib/index.spec.ts

@@ -0,0 +1,15 @@
+import { cleanClass } from '$lib';
+
+describe('cleanClass', () => {
+  it('should return a string of class names', () => {
+    expect(cleanClass('class1', 'class2', 'class3')).toBe('class1 class2 class3');
+  });
+
+  it('should filter out undefined, null, and false values', () => {
+    expect(cleanClass('class1', undefined, 'class2', null, 'class3', false)).toBe('class1 class2 class3');
+  });
+
+  it('should unnest arrays', () => {
+    expect(cleanClass('class1', ['class2', 'class3'])).toBe('class1 class2 class3');
+  });
+});