code (#369)

Author: arthurfiorette

.changeset/happy-birds-breathe.md

@@ -0,0 +1,5 @@
+---
+'@kitajs/html': patch
+---
+
+Allow undefined in style attributes

packages/html/index.js

@@ -264,6 +264,10 @@ function attributesToString(attributes) {
     // @ts-expect-error - this indexing is safe.
     value = attributes[key];
 
+    if (value === null || value === undefined) {
+      continue;
+    }
+
     // React className compatibility.
     if (key === 'className') {
       // @ts-expect-error - both were provided, so use the class attribute.
@@ -317,10 +321,6 @@ function attributesToString(attributes) {
       continue;
     }
 
-    if (value === null || value === undefined) {
-      continue;
-    }
-
     result += ' ' + key;
 
     if (type !== 'string') {

packages/html/test/style.test.tsx

@@ -15,6 +15,15 @@ describe('Style', () => {
     );
   });
 
+  test('accepts undefined', () => {
+    assert.equal(
+      <div style={{ backgroundColor: undefined }}></div>,
+      '<div style=""></div>'
+    );
+
+    assert.equal(<div style={undefined}></div>, '<div></div>');
+  });
+
   test('CSSProperties', () => {
     const style: JSX.CSSProperties = {
       color: 'red',