Fixed intersectMany function

[matteoscaramuzza]

This change fixes issue #159.
The previous intersectMany method was not finding the correct occurrences.

[micheleriva]

This is good, thank you so much!
Would you mind adding some tests so we make sure we're catching the right occurrences at this point?

Thanks!

[matteoscaramuzza]

Done 👍🏻

Let me know if you need anything else.

Grazie!

[micheleriva]

Left a couple of comments, could you please add tests on array intersection specifically?
Something like:

const arr1 = [1,2,3]
const arr2 = [2,3,4]

const intersection = intersectMany(arr1, arr2) // 2,3

thanks!

[matteoscaramuzza]

I've just added the requested test.
I've also create the type alias and put it inside the datasets folder.

thanks!

[micheleriva]

I left a couple of comments, remember to run the linter before committing 🙂

Thanks again!

[micheleriva]

LGTM thanks!