feat(isISO6391): add isISO6391() functionality

[ezkemboi]

• closes Add isISO6391() method #989

[tux-tn]

isISO6391('xx') will return true even if xx is not a valid ISO 639-1 code
Don't you think that having a regex with all possibilities is more accurate since ISO 639-1 is a standardized list?

[ezkemboi]

@tux-tn, good suggestion. Let me check how long is the list of the codes.

[tux-tn]

@ezkemboi any progress? I needed an ISO639-1 validation regex today and found this gist

[ezkemboi]

@tux-tn let me work on this today evening or tomorrow and update it.
Sorry for any delay caused.

[ezkemboi]

this gist

I think this will help.
I will check out and use it.

Thanks.

[tux-tn]

@ezkemboi take your time! Thank you for working on this

[ezkemboi]

@tux-tn, I have fixed the code, though after running the test, it has changed many more files.

[ezkemboi]

Ping @profnandaa @tux-tn

[profnandaa]

See my minor suggestion, and also remove the unrelated changes.

[profnandaa]

Instead of a regex, could we just use a set instead? Listing the items on each line for better readability:

const isoSet = new Set([
  'aa',
  'ab',
  //...
]);

and return isoSet.has(str).

[ezkemboi]

Alright, thanks, looking at making the requested changes.

[ezkemboi]

@profnandaa I have tried to fix them.
Though, I don't know why some of the files still get generated when we merge upstream to our local branches?

[profnandaa]

@ezkemboi -- make sure you rebase with the latest validatorjs:master.

[profnandaa]

@ezkemboi -- could you also check my comments here, let's check if there's any demand for this...

The idea here to try as much as possible (unless compelled by demand), to have the checking-against-db-ish sort of features, and strictly stick to regex.

I'd prefer that we put this PR on hold until a sizable number of vote is met; like what I saw with isLocale.

-na

[ezkemboi]

That is awesome @profnandaa.