Benchmark JSON parsing with symbol keys

main.rb

require 'active_support/core_ext/hash'
require 'benchmark/ips'
require 'json'

N = 1000
M = 100

TEST_ARRAY = N.times.map do |n|
  h = { 'some_key' => "H #{n}" }
  M.times do |m|
    h = { h: h }
  end
end

TEST_HASH = { array: TEST_ARRAY }

TEST_JSON = TEST_HASH.to_json

Benchmark.ips do |x|
  x.report("JSON.parse(symbolize_names: true)") do
    JSON.parse(TEST_JSON, symbolize_names: true)
  end
  x.report("JSON.parse then deep_symbolize_keys") do
    JSON.parse(TEST_JSON).deep_symbolize_keys
  end
end