I think we can find a better name for this function because it doesn't actually "toggle" anything (i.e. it doesn't modify any object's state based on its current state).

I can't really think of a good name for it as it is written here, though. I recommend splitting it into to distinct methods: `StopwatchPanel#showButtons` and `StopwatchPanel#hideButtons`. It's usually nicer to have one method instead of two, but as it stands, `StopwatchPanel#toggle` is always invoked twice, anyway.

Besides being easier to understand, implementing this as `StopwatchPanel#showButtons` and `StopwatchPanel#hideButtons` lets you factor out the element de-referencing.

To give you an idea of what I mean, here's how you could update the patch to use the new methods:

```diff
- this.toggle(this.nodes.pause, this.nodes.start, this.nodes.resume);
- this.toggle(this.nodes.lap, this.nodes.reset);
+ this.showButtons('pause', 'lap');
+ this.hideButtons('start', 'resume', 'reset');
```