We used to throw if event listener is not a function in Stack:

```js
ReactDOM.render(
  <h1 onClick={{}}>Hello World!</h1>,
  document.getElementById('container')
);
```

<img width="565" alt="screen shot 2017-08-08 at 3 41 08 pm" src="https://user-images.githubusercontent.com/810438/29077502-2646412e-7c50-11e7-8c99-3b7f6c0a2589.png">

Fiber silently ignores this.

I think we should throw. This would let us add support for objects (e.g. for passive listener configuration) if we want to in a minor rather than a major.
setInnerHTML(domElement, propValue);
    } else if (propKey === CHILDREN) {
      setTextContent(domElement, propValue);
    } else if (isCustomComponentTag) {
      if (propValue != null) {
        DOMPropertyOperations.setValueForAttribute(
          domElement,
          propKey,
          propValue,
        );
      } else {
        DOMPropertyOperations.deleteValueForAttribute(domElement, propKey);
      }
    } else if (propValue != null) {
      DOMPropertyOperations.setValueForProperty(domElement, propKey, propValue);
    } else {
      
      
      
      DOMPropertyOperations.deleteValueForProperty(domElement, propKey);
    }
  }
}
var ReactDOMFiberComponent = {
  createElement(
    type: *,
    props: Object,
    rootContainerElement: Element | Document,
    parentNamespace: string,
  ): Element {