It seems like you meant:

```diff
  function isVisibleWorkaround(callback) {
-   document.addEventListener('visibilitychange', this);
+   document.addEventListener('visibilitychange', callback);
```

...if my suggestion is correct, there's a lot more that would need to be changed. You'd need to:

- move that binding to within the `else` branch of the conditional that follows
- store the timeout ID and pass it to `clearTimeout` from the `visibilitychange` handler
- unbind the `visibilitychange` handler in the function passed to `setTimeout`

Or am I misunderstanding the `isVisibilityWorkaround` function?