Errors.on equilvalent on Rails 4

Rails
#1

Hello!

I’m starting with RoR today, but I buy a RoR 3.2 book, and my
installation
on Ubuntu is Rails 4 and Ruby 2.0.

Anyway, in book I have this code:

article.errors.on(:title)

But, not works in Rails 4.

2.0.0-p247 :074 > article.errors.on(:title)NoMethodError: undefined
method on' for #<ActiveModel::Errors:0x0000000427e238> from (irb):74 from /home/patrick/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/commands/console.rb:90:instart’
from
/home/patrick/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/commands/console.rb:9:in
start' from /home/patrick/.rvm/gems/ruby-2.0.0-p247/gems/railties-4.0.0/lib/rails/commands.rb:64:in<top (required)>’
from bin/rails:4:in require' from bin/rails:4:in'2.0.0-p247 :075 >

What is equivalent

on( )

method?

Thanks!

#2

On Sun, Sep 22, 2013 at 9:23 PM, Patrick Maciel Campos
[email protected] wrote:

I’m starting with RoR today, but I buy a RoR 3.2 book, and my installation
on Ubuntu is Rails 4 and Ruby 2.0.

Anyway, in book I have this code:

article.errors.on(:title)
But, not works in Rails 4.

On was deprecated and removed in Rails 4… I’m surprised that author
would have even left something like that in a Rail 3.2 guide since it
would have hindered future development… either way, to address your
issue now you simply do errors[:title] to pull your error. If you
are looking for it to return true or false then you should do
errors[:title].present? or you can use blank? if you please.