Not removing them resulted in leaks as we would hold on to removed nodes forever.
This really showed up with images and the load event where we would unmount and create a new img with the same react id as the old one. We properly cleared and primed the caches but we would handle the load event for both nodes. We would eventually hit an invariant in that path as we tried to handle the event for the removed node, which no longer matched the node we had in the cache.
By forcefully removing the listener, we'll avoid this problem entirely and we should leak fewer DOM nodes.
If the event is on the window object, topScroll, for instance, the topLevelTarget will not have getAttribute defined. Restore the previous `|| !topLevelTarget.attributes` check to avoid an error on every scroll.
I find myself often using (modified) examples to test in IE and it's a pain to have to add the shims in every time. Might as well just add them in always.
Can be run with `node_modules/.bin/jest` for now; didn't want to disturb the grunt setup.
Right now one test fails with:
```
FAIL browser/ui/__tests__/ReactDOMComponent-test.js (1.423s)
● ReactDOMComponent › updateDOM › it should update styles when mutating style object
- Expected: '0' toEqual: '0.5'
at Spec.<anonymous> (src/browser/ui/__tests__/ReactDOMComponent-test.js:99:33)
```
which I can only assume is a jsdom problem -- no other asserts fail.
cf. #1376.
This is useful for SVG. Dynamically adding and removing `<title>` elements in SVG still won't work properly because of getMarkupWrap but this at least lets you include it in initial render and then unmount the entire `<svg>` without problems.
The previous examples didn't properly work when 1) a Store callback does
waitFor on Stores that haven't been reached yet and 2) a Store callback
waits on another Store that is already waiting.
The updated example uses constructs Promises up front and then
asynchronously resolves them.
For boolean-like objects, I've added hasOwnProperty checks in addition to the existing truthiness check even though for most of these dicts, we leave out false keys instead of setting them explicitly to false.
In DOMPropertyOperations, we don't need to check hasOwnProperty if the property is in isStandardName because (with the exception of getPossibleStandardName) the dicts on DOMProperty will now be consistently populated with every valid attribute.