Create 2012-12-28-undefined-props-on-numbers.md

New post about unexpected undefined properties on numbers

Signed-off-by: DTrejo <david.daniel.trejo@gmail.com>

README.md

@@ -72,3 +72,4 @@ Ordered by date of first contribution.
 - [Jamund Ferguson aka `xjamundx`](https://github.com/xjamundx)
 - [Thaddee Tyl aka `espadrine`](https://github.com/espadrine)
 - [Stanley Stuart aka `fivetanley`](https://github.com/fivetanley)
+- [Ben Combee aka `unwiredben`](https://github.com/unwiredben)

package.json

@@ -1,7 +1,7 @@
 {
   "name": "wtf",
   "description": "The wtfs of javascript at wtfjs.com",
-  "version": "0.2.0-21",
+  "version": "0.2.0-24",
   "homepage": "wtfjs.com",
   "repository": {
     "type": "git",
@@ -29,4 +29,4 @@
     "wtfjs.com",
     "www.wtfjs.com"
   ]
-}
+}

posts/2012-12-28-undefined-props-on-numbers.md

@@ -0,0 +1,15 @@
+```
+    function getBounds(node) {
+        var n = node || 0;
+        return { width: n.width, height: n.height };
+    }
+```
+
+If you call `getBounds()` with _null_, you'll get back `{ width: undefined, height: undefined }`
+because in JS, numbers have properties (inherited from Number), and using an undefined
+property doesn't throw, it just returns undefined.  `null` and `undefined` are propertyless.
+Definitely not what I expected in a quick reading of code like this.
+
+— [@unwiredben][1]
+
+[1]:https://twitter.com/unwiredben