SpaceSniffer is not available for Mac but there are plenty of alternatives that runs on macOS with similar functionality. The best Mac alternative is Baobab Disk Usage Analyzer, which is both free and Open Source.
Sadly, there is no version of SpaceSniffer for Mac, but there are some other tools that you can try instead. Here is a list of programs that can serve as replacements for SpaceSniffer for Mac.
Using a Mac disk space analyzer can help you identify old and duplicate files that can be deleted to provide more free space for future activity. Before we dive into the picks, the short video below shows safe, built-in ways to free up space on your Mac.