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Extending the Hash Class in a Rails Application

I have a rails application where I need to extend a module Hash

to add a method -

class Hash
  def delete_blank
    delete_if{|k, v| v.nil? or (v.instance_of?(Hash) and v.delete_blank.empty?)}
  end
end

I created a file called hash_extensions.rb and put it in the lib folder and of course set up the autoload paths with the following line inconfig/application.rb 

config.autoload_paths += %W(#{config.root}/lib)

When I call the delete blank method on the Hash, I get the following error:

undefined method `delete_blank' for #<Hash:0x000000081ceed8>\nDid you mean?  delete_if

In addition to this, I also tried to place require "hash_extensions"

at the top of the file from which I am calling the delete_blank method.

What am I doing wrong here, or can I avoid extending Hash to have the same functionality?

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1 answer


You can solve this problem in several ways:



  • Assuming what hash_extensions.rb

    's under your_app/lib/extensions

    . (It is recommended to keep all extensions in a separate folder), all extensions in config/application.rb

    must be listed below:

    Dir[File.join(Rails.root, "lib", "extensions", "*.rb")].each {|l| require l }

  • Move hash_extensions.rb

    under config/initializers

    and it should be automatically loaded.

  • Create a folder lib

    or extensions

    sub your_app/app

    and drag hash_extensions.rb

    it to it, and Rails will take care of loading it.
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