then this guy only completed 7 Katas lol. how ironic

I had no idea that slice floors the result! Very informative, thank you!

⬆️ this.comment

you time yourself????

People in here are talking mad shit because they cant get away from assuming that everyone on this website is at their level. For some of us, like myself, ive been teaching myself for > 6 months, we dont know how to do everything in one line, and we dont always know when to use one solution vice another. Please chill out.

Nice one, didn't even remeber this while solving it

Sometimes you just make it work and then think of chaning the style :)

Tbh, this was my first answer as well as I couldn't remember any JS functions while timing myself. I am aware that it could be cleaned up a lot. Wouldn't having a working solution be better than no solution at all?

I suspect you're here to be funny
我怀疑你是来搞笑的

1. the reduce function is accumulating the product of the complicated expression with a* (a is the accumulator)
2. the +"" is for converting the number in the array to a string, this is needed so we can use an index to get the first digit
3. [0] is taking the first digit of the string
4. earlier in the code, the first + is the unary plus operator, used for converting that digit (which is now a string) back into a number so we can perform math on it again (otherwise the next + would be a string concatenation operation rather than an addition operation).
5. arr[i-1]%10 is taking the last digit of the previous number element
6. the /arr[0] at the end is needed because the initial value that ends up getting multiplied is going to be the first number of the array. Alternatively, this could have been removed, and an initial value of 1 could have been provided as the 2nd parameter of the .reduce() call, after the reducer callback function. However, they didn't want to do it that way because then they couldn't use [i - 1] as an index, as it would change the starting value of i from 1 to 0.

I hope this helps.

same

why? I don't see a picture of you there.

This is the pure reason why switch statement exists. It is so messy and needs a refactoring. Should not have so many best practices upvotes. Also, there are much more cleaner solutions.

Best solution but not an unreadable one liner so won't be voted highly...

Thanks for the explanation. That's very clever.