Feature/attributes (#9)

* Remove special properties

parcel@next (2) introduce these special properties to map back to where the element originates.
Neat stuff. Crashes everything.

* Make sure domdom doesn't crash and burn when a attribute is undefined

* 4.11.12

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@eirikb/domdom",
-  "version": "4.11.11",
+  "version": "4.11.12",
   "description": "The proactive web front-end framework for the unprofessional",
   "scripts": {
     "build": "tsdx build",

src/index.ts

@@ -68,9 +68,11 @@ export function domdom(parent?: HTMLElement, view?: Domponent): Domdom | Data {
         }
       }
 
-      for (let [key, value] of Object.entries(props || {})) {
+      for (let [key, value] of Object.entries(props || {}).filter(
+        ([key]) => !key.startsWith('__')
+      )) {
         const valueAsHodor = value as Hodor;
-        if (valueAsHodor.isHodor) {
+        if (valueAsHodor && valueAsHodor.isHodor) {
           valueAsHodor.element = element;
         }
 
@@ -79,7 +81,7 @@ export function domdom(parent?: HTMLElement, view?: Domponent): Domdom | Data {
           const event = key[2].toLowerCase() + key.slice(3);
           element.addEventListener(event, (...args) => {
             const valueFn = value as Function;
-            if (valueFn !== null) {
+            if (valueFn !== undefined) {
               return valueFn(...args);
             }
           });

test/index.test.tsx

@@ -1539,3 +1539,8 @@ test('on with properties', async t => {
   });
   t.is(await html(), '<div><div>a: A!</div><div>b: B!</div></div>');
 });
+
+test('properties without value should not crash', async t => {
+  append(document.body, () => <div style={undefined}></div>);
+  t.is(await html(), '<div style=""></div>');
+});