Just for clarity sake, can we please have it as:
```
return (! record.getLayer().isBaseLayer) && (record.getLayer().displayInLayerSwitcher);
```
Although I'm not sure about it. Or just:
```
return (! record.getLayer().isBaseLayer) && record.getLayer().displayInLayerSwitcher;
```

Either way, have a space after the `!`.