It's not quite type safety, it's all about order, and it's definitely not specific to Javascript. Here's Python3: >>> sorted([10, 2, math.nan]) [2, 10, nan

It's not quite type safety, it's all about order, and it's definitely not specific to Javascript. Here's Python3: >>> sorted([10, 2, math.nan]) [2, 10, nan] >>> sorted([10, math.nan, 2]) [10, nan, 2]