You missed @gruehle's comment that you don't need to check for '.', '..', or '...' that got buried in a hidden "outdated diff" comment thread.

I just noticed that you are using single-quotes for literal strings and Brackets team prefers double-quotes.

Sorry for the last minute comment, but do you think it would be more efficient to put this in a regex? Something like:

```
    var _illegalFilenamesRegex = /^(com\d|lpt\d|nul|con|prn|aux)$/;
```

Note: that regex also matches com0 and lpt0 which are not in the original array. If that's a problem, \d can be changed to [1-9].