Module: Featuring::Flaggable

Defined in:
lib/featuring/flaggable.rb

Overview

Internal concerns related to defining feature flags on a module or class.

Defined Under Namespace

Modules: ClassMethods, InstanceMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(object) ⇒ Object 



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# File 'lib/featuring/flaggable.rb', line 11

def self.extended(object)
  super

  case object
  when Class
    object.include object.internal_feature_checks_module
  when Module
    object.extend object.internal_feature_checks_module
  end
end

.setup_flaggable_object(object) ⇒ Object 



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# File 'lib/featuring/flaggable.rb', line 22

def self.setup_flaggable_object(object)
  case object
  when Class
    object.extend ClassMethods
    object.prepend InstanceMethods
  when Module
    object.extend Flaggable
    object.extend Delegatable
    object.extend Serializable
  end
end

Instance Method Details

#define_feature_flag(name, default, &block) ⇒ Object 



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# File 'lib/featuring/flaggable.rb', line 46

def define_feature_flag(name, default, &block)
  # Define a feature check method that returns the default value or the block's return value.
  #
  internal_feature_module.module_eval do
    if method_defined?(name)
      undef_method(name)
    end

    if block
      define_method name, &block
    else
      define_method name do
        default
      end
    end
  end

  # Define a method that typecasts the value returned from the delegator to true/false. This is
  # the method that's called when calling code asks if a feature is enabled. It guarantees that
  # only true or false is returned when checking a feature flag.
  #
  internal_feature_checks_module.module_eval do
    method_name = "#{name}?"

    if method_defined?(method_name)
      undef_method(method_name)
    end

    define_method method_name do |*args|
      fetch_feature_flag_value(name, *args)
    end
  end

  # Keep track of the feature flag we just defined.
  #
  feature_flags << name
end

#feature_flags ⇒ Object 



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# File 'lib/featuring/flaggable.rb', line 84

def feature_flags
  @_feature_flags ||= []
end

#internal_feature_checks_module ⇒ Object

Contains methods that wrap the original values to typecast them into true or false values.



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# File 'lib/featuring/flaggable.rb', line 42

def internal_feature_checks_module
  @_internal_feature_checks_module ||= Module.new
end

#internal_feature_module ⇒ Object

Contains methods that return the feature’s original default value, or block value.



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# File 'lib/featuring/flaggable.rb', line 36

def internal_feature_module
  @_internal_feature_module ||= Module.new
end