Discussion on: [Challenge] 🐝 FizzBuzz without if/else

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Thanks for the fun challenge!

I'm not sure if JavaScript's type conversion is considered cheating, but I thought it was cool and wanted to share!

const n = 15;

let output = new Array(n).fill(null);

output = output.map((_value, index) => {
    let offsetIndex = index + 1;

    return (["", "Fizz"][!(offsetIndex % 3) + 0] + ["", "Buzz"][!(offsetIndex % 5) + 0]) || offsetIndex;
});

console.log(output);

ogrotten • Jul 17 '20

why _value?

I understand that the 'convention' for _ is for private, but is there some other use for it here?

Or is it just habit 😂

SavagePixie • Jul 17 '20

It is also a convention for unused parameters.

Keff • Jul 17 '20

Thanks for sharing Jesse!! It's a really neat solution 🤘!
Also not cheating at all!

ogrotten • Jul 17 '20 • Edited

Hmm... As a bootcamp student, I'm trying to untangle this.

[!(offsetIndex % 3) + 0]
I see this checks the modulus, and inverts the result. Any non-zero int is truthy, and this expression makes it false . . . +0 to coerce the false to an int. That is enough that the entire thing evaluates falsy, which then results in outputting offsetIndex on the otherside of the or. I had to drop this in a node repl to follow it, but I eventually got it 😁

But what is the ["", "Fizz"][!(offsetIndex % 3) + 0] double-array looking thing there? I thought it was a 2d array at first, but that doesn't seem right for a number of reasons.

Corey Alexander • Jul 18 '20

I'm pretty sure the first pair of square brackets creates an array, and the second one indexes into that array. So I think they are array indexing into the first array with either 0 or 1 to pick the empty string or "Fizz" depending on the offsetIndex!

Hope that helps!

Keff • Jul 18 '20

yup, it defines the array first const array = ["", "Fizz"] and then access the index array[!(offsetIndex % 3) + 0]. The expression will resolve either to true+0 -> 1 or false+0 -> 0

ogrotten • Jul 18 '20

holy shit. that's cool.

I THOUGHT it might have been something like that, but I was thinking about it wrongly . . . I wasn't thinking of it as the array followed by the index, I was thinking of it as a variable. So ["an", "array"] was the name of the array, and then it had it's own index. Not very practical.

But the actual use is quite cool and makes plenty sense.

Thanks!