Average is NaN with 0 solves

[YTCuber]

To reproduce, clear all solves.
Click on "Stats", then click on "More Stats".
It shows you "Average - NaN:NaN.NaN".

While this is understandable for any JavaScript programmer, any other person will think, that the timer is broken.

Possible solutions are displaying "DNF", "00:00.00" or "can not calculate". You can do this in averageOfArray (line 260 in script.js) by checking like if(array.length<1)return"DNF".