feat(attributes-to-props): check for overloaded boolean values

For HTML DOM attributes that can be either boolean or string,
make sure to convert the value correctly for React.

Add test to confirm `download` attribute is properly converted.

Author: remarkablemark

lib/attributes-to-props.js

@@ -33,11 +33,11 @@ function attributesToProps(attributes) {
     // convert HTML attribute to React prop
     property = HTMLDOMPropertyConfig[attributeName.toLowerCase()];
     if (property) {
-      if (property.hasBooleanValue) {
-        props[property.propertyName] = true;
-      } else {
-        props[property.propertyName] = attributeValue;
-      }
+      props[property.propertyName] =
+        property.hasBooleanValue ||
+        (property.hasOverloadedBooleanValue && !attributeValue)
+          ? true
+          : attributeValue;
       continue;
     }
 

test/attributes-to-props.js

@@ -109,6 +109,26 @@ describe('attributesToProps', () => {
         }
       );
     });
+
+    it('converts overloaded boolean attributes', () => {
+      assert.deepEqual(
+        attributesToProps({
+          download: ''
+        }),
+        {
+          download: true
+        }
+      );
+
+      assert.deepEqual(
+        attributesToProps({
+          download: 'filename'
+        }),
+        {
+          download: 'filename'
+        }
+      );
+    });
   });
 
   describe('SVG', () => {