Would it be useful to prefilter per cards?

[aloisdg]

Hi!

Let's look at the main example from the readme.

var card = Dedge.Cardidy.Identify("4127540509730813").Single();
Console.WriteLine(card); // print Visa

Let's say that as a dev, we would like to know if a given card is a Visa. The current code would be a good enough way. To work Identify() has to walk every card until the find a matching one.

Basically here is how Cardidy currently works:

var list = new [] { Amex, MC, Mir, Foo, Bar, Visa }

var results = list.Where(card => card is matching)
return results;

We could improve that by passing a prefiltered list to Indentify().

var card = Dedge.Cardidy.Identify("4127540509730813", where: new[]{Visa}).Single();
Console.WriteLine(card); // print Visa

and inside we would do:

var list = prefiltered == null || !prefiltered.Any() ?  new [] { Amex, MC, Mir, Foo, Bar, Visa } : prefiltered;
var results = prefiltered.Where(card => card is matching);
return results;

Yay or nay? Since there is not a lot of card I am not sure that we gain much by doing that.

[hey24sheep]

That is a good "user defined filter" if a user/client needs to make a check for a particular card only and don't want to run "card check" against "all cards list".

In any case your complexity will always be O(n).

[aloisdg]

True. I am not sure if it is really worth it. We have currently 28 cards and most of them doesn't have much ranges to be tested...

[aloisdg]

I will close this one for now.