decorate_collection 用在 集合 上，decorate 用在实例上。

• decorate_collection -> Article.all 或者 Article.where(condition) 或者 Article.where(condition).filter(condition) -> 返回一个集合
• decorate -> Article.first 或者 Article.find(condition) 或者 Article.find_by(condition) 或者 Article.where(condition).filter(condition).detect(condition) -> 返回一个实例

盲猜：

# 以下等价
ArticleDecorator.decorate_collection(Article.all)
Article.all.each(&:decorate)
# 以下等价
Article.first.decorate
ArticleDecorator.decorate_collection([Article.first])

如有这个能力为什么去贵公司？贵公司有什么过人之处？

I agree with you.

It is really a little too expensive. I read almost all his blogs. Although I've always wanted to buy this book on impulse, my pocket always pulls me back to reality.

不懂就问，你心目中的面试是怎么面试？

2.6.5 (main):0 > Podcast.frequencies
=> {"unknown"=>0, "daily"=>1, "weekly"=>7, "biweekly"=>14, "monthly"=>31, "periodic"=>366}
2.6.5 (main):0 > Podcast.where(frequency: ["daily", "weekly"]).count
   (14.0ms)  SELECT COUNT(*) FROM "podcasts" WHERE "podcasts"."frequency" IN ($1, $2)  [["frequency", 1], ["frequency", 7]]
=> 4317
2.6.5 (main):0 > Podcast.ransack(frequency_in: ["daily", "weekly"]).result.count
   (11.6ms)  SELECT COUNT(*) FROM "podcasts" WHERE "podcasts"."frequency" IN (0, 0)
=> 166
2.6.5 (main):0 > Podcast.ransack(frequency_in: [1, 7]).result.count
   (14.9ms)  SELECT COUNT(*) FROM "podcasts" WHERE "podcasts"."frequency" IN (1, 7)
=> 4317

打破零回复。 很多前端包，比如 select2可以直接打包 yarn add select2引入了。

啊 啊啊 今天上午是你？

刚入职场的年轻工程师如何判断他/她所要投资的技术是像 2006 年左右的 Rails、2007 年左右的 Hadoop、还是更像 2010 年前后的 MongoDB？有点像投资创业公司，如何押对宝？还是尽量选择无聊的成熟的老技术、专注于解决实际问题、白猫黑猫抓到老鼠就是好猫？

但是呢，新人毕竟是新人，一头雾水，就想经常逃课的人，要考试了一样，不先看重点，而是去钻研难题，死翘翘了

这么酷炫的技巧...

def before_action(method_name, options)
  action_module = Module.new do
    send :define_method, options[:for] do |*args, &block|
      send method_name

      super(*args, &block)
    end
  end

  prepend action_module
end

恍然大悟，突然想起来之前遇到的一个 bug...

最后一个插件就是针对 VIM 的

1. action_name == "create" 
2. params[:action] == "create" 
3. request.post?

你这个帖子，为什么没有被和谐掉！

=== 等价于 case when 中的条件判断：

condition = 'hello'
case condition
when String
when User
When (1...10)
when /ello/
end

更侧重归属感。

啊哈，以为有什么暗黑高科技

我是在 ActiveSupport 扩展里面看到的，想请教一下，你是怎么定位源码的位置的？

# use helper
2.3.3 (main):0 > helper.number_to_currency 7777777
=> "¥ 7,777,777.00"
# active_support
2.3.3 (main):0 > 7777777.to_s(:currency)
=> "¥ 7,777,777.00"
# include precision
2.3.3 (main):0 > 7777777.to_s(:currency, precision: 3)
=> "¥ 7,777,777.000"

这帖子还吵起来了

class A
  define_singleton_method :loudly do |message|
    puts message.upcase
  end
end

A.loudly "my message"

哈哈哈哈哈嗝

AA 是想插入的值/?

整理的简直了... 赞

1. gen install bundler
2. bundle install

问题如下：

» c                                                                                                                                                                                                                                                                                                                                                [ruby-2.4.0][10:00:54]
/Users/dubing/.rvm/rubies/ruby-2.4.0/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- bundler/setup (LoadError)
        from /Users/dubing/.rvm/rubies/ruby-2.4.0/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /Users/dubing/workspace/vcooline/code_event_back_service/config/boot.rb:3:in `<top (required)>'
        from bin/rails:3:in `require_relative'
        from bin/rails:3:in `<main>'

1. 重新安装bundler: gem install bundler

   Fetching: bundler-1.16.2.gem (100%)
   Successfully installed bundler-1.16.2
   1 gem installed
   

2. 然后bundle install

然后世界顺畅了。

» c                                                                                                                                                                                                                                                                                                                                                [ruby-2.4.0][10:04:32]
Loading development environment (Rails 5.0.2)
gem install awesome_print  # <-- highly recommended
2.4.0 (main):0 >

自己 200 块提心吊胆，别人投了 200W, 旅游北西东南...

学习到了，你好认真，灰常谢谢你提供的详细的解释。学习了。

我在处理的时候是这样写的

class User < ApplicationRecord
 avatar
    super || 'default value'
  end 
end

你的写法，比我的优雅了太多了。相形见绌。

No effect

你这里只是使用了 attr_accessor, 接着... 这个是为了，有些人没有上传头像，才会调用默认头像, 可是你这种就会，一直使用默认头像，毕竟 real_avatar始终是空。

user model:

class User < ApplicationRecord

  def avatar
    real_avatar.present? ? "real_avatar" : "default.png"
  end

  alias :real_avatar :avatar
end

执行结果：

2.4.2 (main):0 > user = User.last
  User Load (0.6ms)  SELECT  "users".* FROM "users" ORDER BY "users"."id" DESC LIMIT $1  [["LIMIT", 1]]
=> #<User:0x00007fd3cc9330a8
 id: 2,
 uid: "017526292153702",
 avatar: "http://img2.imgtn.bdimg.com/it/u=3563567972,3348399262&fm=27&gp=0.jpg",
 nickname: "Nick-member",
 created_at: Fri, 19 Jan 2018 00:26:16 CST +08:00,
 updated_at: Fri, 19 Jan 2018 00:26:16 CST +08:00>
2.4.2 (main):0 > user.avatar
SystemStackError: stack level too deep
from /Users/dubing/workspace/vcooline/group_buying_front/app/models/user.rb:18:in `avatar'
2.4.2 (main):0 >