Hello, I am a beginner and I have difficulty with the description. (I don't understand)
Could someone explain to me.

I encountered the same issue. I think the test code is faulty.

Please I think you should review the last few incProgress tests. It should be from (8, 7, 91) to (8, 8, 1) then finally (8, 8, 4). It's preventing my code from passing the tests.

Kata are rated based on community vote. This kata was published a little over 11 years ago, when the community was very new. The community has gotten more skilled, educational resources have become a lot more accessible, and expectations around coding proficiency have increased over time. You're correct that if this kata were to be rated today, it would likely be voted as a 6-kyu kata, but ranks are very difficult to change and it's not worth going through the long process to do so in 99% of cases. Just be happy with your easy points.

interesting

null does not have any methods, in particular it does not have a filter() method, this is why your code throws an error when called with null. this is consistent across all JavaScript implementations and has nothing to do with the environment. you have to add an explicit guard for null, since it is a valid input in this kata (which is not good practice, but that's besides the point)

There are several problems in your code.

Not a kata issue.

fixed. i also moved the testing code out of preloaded and tried to improve the code quality of the tests suite a bit.

Hi,

Are you sure that the test case with { "" } is correct? It is not a null-terminated array, how are users expected to figure out where the array ends?

Thanks!

the error feedback message says

expected undefined to equal 23

Which means your code should be returning 23, but it returns undefined because it doesn't return anything. To pass kata you need to return a value, not print it.