Class: Darthjee::CoreExt::Hash::ValueChanger

Inherits:
Object
  • Object
show all
Defined in:
lib/darthjee/core_ext/hash/value_changer.rb

Overview

Class responsible for changing values on a hash

Examples:

changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  recursive: false,
  skip_inner: false,
  &:class
)

hash = { a: 1, b: { c: 2 }, d: [{ e: 1 }] }
changer.change(hash)  # {
                      #   a: Integer,
                      #   b: Hash,
                      #   d: Array
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new do |value|
  value.to_s.size
end

hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
changer.change(hash)  # {
                      #   a: 2,
                      #   b: { c: 1 },
                      #   d: [{ e: 3 }]
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  skip_inner: true
) do |value|
  value.to_s.size
end

hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
changer.change(hash)  # {
                      #   a: 2,
                      #   b: 11,
                      #   d: 7
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  recursive: true
) do |value|
  value.to_s.size
end

hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
changer.change(hash)  # {
                      #   a: 2,
                      #   b: { c: 1 },
                      #   d: [{ e: 3 }]
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new do |value|
  value.to_s.size
end

array = [15, { c: 2 }, [{ e: 100 }]]

changer.change(array) # [
                      #   2,
                      #   { c: 1 },
                      #   [{ e: 3 }]
                      # ]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(recursive: true, skip_inner: true, &block) ⇒ ValueChanger

Returns a new instance of ValueChanger.

Examples:

changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  recursive: false,
  skip_inner: false,
  &:class
)

hash = { a: 1, b: { c: 2 }, d: [{ e: 1 }] }
changer.change(hash)  # {
                      #   a: Integer,
                      #   b: Hash,
                      #   d: Array
                      # }

Parameters:

  • recursive (Boolean) (defaults to: true) —

    flag telling to apply transformation recursively

  • skip_inner (Boolean) (defaults to: true) —

    flag telling to not apply change block call to inner hashes

  • block (::Proc) —

    block to be called when changing the values



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# File 'lib/darthjee/core_ext/hash/value_changer.rb', line 44

def initialize(recursive: true, skip_inner: true, &block)
  @recursive = recursive
  @skip_inner = skip_inner

  @block = block
end

Instance Attribute Details

#block ⇒ Object

block to be called when changing the values



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# File 'lib/darthjee/core_ext/hash/value_changer.rb', line 20

class ValueChanger
  attr_accessor :recursive, :skip_inner, :block

  # @param [Boolean] recursive
  #   flag telling to apply transformation recursively
  # @param [Boolean] skip_inner
  #   flag telling to not apply change block call to inner hashes
  # @param [::Proc] block
  #   block to be called when changing the values
  #
  #
  # @example
  #   changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  #     recursive: false,
  #     skip_inner: false,
  #     &:class
  #   )
  #
  #   hash = { a: 1, b: { c: 2 }, d: [{ e: 1 }] }
  #   changer.change(hash)  # {
  #                         #   a: Integer,
  #                         #   b: Hash,
  #                         #   d: Array
  #                         # }
  def initialize(recursive: true, skip_inner: true, &block)
    @recursive = recursive
    @skip_inner = skip_inner

    @block = block
  end

  # Change the given object
  #
  # @return the resulting object (hash or array)
  #   with it`s values changed
  # @param [::Hash/::Array] object
  #   object to have it's values changed
  #
  # @example
  #   changer = Darthjee::CoreExt::Hash::ValueChanger.new do |value|
  #     value.to_s.size
  #   end
  #
  #   hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
  #   changer.change(hash)  # {
  #                         #   a: 2,
  #                         #   b: { c: 1 },
  #                         #   d: [{ e: 3 }]
  #                         # }
  #
  # @example
  #   changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  #     skip_inner: true
  #   ) do |value|
  #     value.to_s.size
  #   end
  #
  #   hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
  #   changer.change(hash)  # {
  #                         #   a: 2,
  #                         #   b: 11,
  #                         #   d: 7
  #                         # }
  #
  # @example
  #   changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  #     recursive: true
  #   ) do |value|
  #     value.to_s.size
  #   end
  #
  #   hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
  #   changer.change(hash)  # {
  #                         #   a: 2,
  #                         #   b: { c: 1 },
  #                         #   d: [{ e: 3 }]
  #                         # }
  #
  # @example
  #   changer = Darthjee::CoreExt::Hash::ValueChanger.new do |value|
  #     value.to_s.size
  #   end
  #
  #   array = [15, { c: 2 }, [{ e: 100 }]]
  #
  #   changer.change(array) # [
  #                         #   2,
  #                         #   { c: 1 },
  #                         #   [{ e: 3 }]
  #                         # ]
  def change(object)
    if object.respond_to?(:change_values)
      change_hash(object)
    elsif iterable?(object)
      change_array(object)
    else
      object
    end
  end

  private

  # Apply change logic to hash object
  #
  # @private
  def change_hash(original_hash)
    original_hash.tap do |hash|
      original_hash.each do |key, value|
        hash[key] = new_value(value)
      end
    end
  end

  # Apply change logic to iterator
  #
  # @private
  def change_array(array)
    method = %w[map! map].find { |m| array.respond_to? m }

    array.public_send(method) do |value|
      if value.respond_to?(:change_values)
        value.change_values(options, &block)
      elsif iterable?(value)
        change_array(value)
      else
        new_value(value)
      end
    end
  end

  # check wehether block should be called over
  # value or not
  #
  # when the block is not iterable (not Array or Hash)
  # or when skip_inner option is set to be false,
  # then block should be called
  #
  # @private
  def change_value?(value)
    !iterable?(value) || !skip_inner
  end

  def iterable?(value)
    value.respond_to?(:each)
  end

  def new_value(value)
    value = block.call(value) if change_value?(value)

    return value unless apply_recursion?(value)

    change(value)
  end

  def apply_recursion?(value)
    iterable?(value) && recursive
  end

  def options
    @options ||= {
      recursive: recursive,
      skip_inner: skip_inner
    }
  end
end

#recursive ⇒ Object

Returns the value of attribute recursive.



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# File 'lib/darthjee/core_ext/hash/value_changer.rb', line 21

def recursive
  @recursive
end

#skip_inner ⇒ Object

Returns the value of attribute skip_inner.



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# File 'lib/darthjee/core_ext/hash/value_changer.rb', line 21

def skip_inner
  @skip_inner
end

Instance Method Details

#change(object) ⇒ Object

Change the given object

Examples:

changer = Darthjee::CoreExt::Hash::ValueChanger.new do |value|
  value.to_s.size
end

hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
changer.change(hash)  # {
                      #   a: 2,
                      #   b: { c: 1 },
                      #   d: [{ e: 3 }]
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  skip_inner: true
) do |value|
  value.to_s.size
end

hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
changer.change(hash)  # {
                      #   a: 2,
                      #   b: 11,
                      #   d: 7
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new(
  recursive: true
) do |value|
  value.to_s.size
end

hash = { a: 15, b: { c: 2 }, d: [{ e: 100 }] }
changer.change(hash)  # {
                      #   a: 2,
                      #   b: { c: 1 },
                      #   d: [{ e: 3 }]
                      # }

changer = Darthjee::CoreExt::Hash::ValueChanger.new do |value|
  value.to_s.size
end

array = [15, { c: 2 }, [{ e: 100 }]]

changer.change(array) # [
                      #   2,
                      #   { c: 1 },
                      #   [{ e: 3 }]
                      # ]

Parameters:

  • object (::Hash/::Array) —

    object to have it’s values changed

Returns:

  • the resulting object (hash or array) with it`s values changed



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# File 'lib/darthjee/core_ext/hash/value_changer.rb', line 110

def change(object)
  if object.respond_to?(:change_values)
    change_hash(object)
  elsif iterable?(object)
    change_array(object)
  else
    object
  end
end