Examples in Intermediate Rails -> Custom Validations can be done w/o custom validations

[droberts-sea]

The custom method one can be validated with inclusion:

class Item < ActiveRecord::Base
  validates :kind, inclusion: { in: %w(Movie Book Album) }
end

Similarly, the one for conditional validations could be achieved with allow_nil and allow_blank:

class User < ActiveRecord::Base
  # If the user provided a username, it must be at least 8 characters
  validates :username, length: { minimum: 8 }, allow_nil: true, allow_blank: true
end

[droberts-sea]

For the custom method, we could use the Luhn algorithm for validating credit cards, but that might require too much contextual overhead.

[droberts-sea]

For tomorrow (C6) I say we just roll with it, we can come back to this for C7 if we have time.

[CheezItMan]

Sure we could use a more complicated example to show a custom validation
and we could do my custom validation with the built-in tools, but the point
is simply to show how a custom validation can be written and used without
having to learn another algorithm as well, for the initial example.

Luhn makes a very good use-case for a followup example or homework however.

That's a good thing to add for C7.

On Tue, Oct 18, 2016 at 11:18 PM, Dan Roberts notifications@github.com
wrote:

For tomorrow (C6) I say we just roll with it, we can come back to this for
C7 if we have time.

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Chris McAnally
Ada Developer Academy Instructor
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