Underscorize Hash

Benchmark underscorize hash

require 'benchmark'
Benchmark.bmbm do |x|
  HASH_TEST = {'a' => 'a',  'b' => { 'c' => {'firstName' => 'd'}, 'e' => 'e'}}

  def convert_hash_keys(value)
    case value
      when Array
       value.map { |v| convert_hash_keys(v) }
      when Hash
        Hash[value.map { |k, v| [underscore_key(k), convert_hash_keys(v)] }]
      else
        value
    end
  end

  def underscore_key(key)
    key.to_s.underscore.to_sym
  end

  x.report("Helper #convert_hash_keys") do
    convert_hash_keys(HASH_TEST)
  end

  x.report("#transform_keys") do
    HASH_TEST.transform_keys{ |key| key.to_s.underscore.to_sym }
  end

  x.report("#with_indifferent_access") do
    HASH_TEST.with_indifferent_access
  end

end

Rehearsal -------------------------------------------------------------
#convert_hash_keys          0.000000   0.000000   0.000000 (  0.000272)
#transform_keys             0.000000   0.000000   0.000000 (  0.000108)
#with_indifferent_access    0.000000   0.000000   0.000000 (  0.000053)
---------------------------------------------------- total: 0.000000sec

                                user     system      total        real
#convert_hash_keys          0.000000   0.000000   0.000000 (  0.000239)
#transform_keys             0.000000   0.000000   0.000000 (  0.000136)
#with_indifferent_access    0.000000   0.000000   0.000000 (  0.000031)