keys-each-vs-each_key.cr

require "benchmark"
puts Crystal::DESCRIPTION

HASH = {
  "provider" => "facebook",
  "uid"      => "1234567",
  "info"     => {
    "nickname"   => "jbloggs",
    "email"      => "joe@bloggs.com",
    "name"       => "Joe Bloggs",
    "first_name" => "Joe",
    "last_name"  => "Bloggs",
    "image"      => "http://graph.facebook.com/1234567/picture?type=square",
    "urls"       => {"Facebook" => "http://www.facebook.com/jbloggs"},
    "location"   => "Palo Alto, California",
    "verified"   => true,
  },
  "credentials" => {
    "token"      => "ABCDEF...",
    "expires_at" => 1321747205,
    "expires"    => true,
  },
  "extra" => {
    "raw_info" => {
      "id"           => "1234567",
      "name"         => "Joe Bloggs",
      "first_name"   => "Joe",
      "last_name"    => "Bloggs",
      "link"         => "http://www.facebook.com/jbloggs",
      "username"     => "jbloggs",
      "location"     => {"id" => "123456789", "name" => "Palo Alto, California"},
      "gender"       => "male",
      "email"        => "joe@bloggs.com",
      "timezone"     => -8,
      "locale"       => "en_US",
      "verified"     => true,
      "updated_time" => "2011-11-11T06:21:03+0000",
    },
  },
}

def slow
  HASH.keys.each(&.chars)
end

def fast
  HASH.each_key(&.chars)
end

Benchmark.ips do |x|
  x.report("Hash#keys.each") { slow }
  x.report("Hash#each_key") { fast }
end