Run zxcvbn.js from ruby with therubyracer

zxcvbn.rb

# therubyracer gem - https://github.com/cowboyd/therubyracer
require 'v8'

password = ARGV[0] || 'password'
ARGV.clear

puts "Testing password: #{password}"
puts

class PasswordStrength
  ZXCVBN_SOURCE = File.read('zxcvbn.js')
  ATTRIBUTES = %w[ entropy crack_time crack_time_display score calc_time ]

  def initialize
    @ctx = V8::Context.new do |ctx|
      ctx.eval('exports = {}')
      ctx.eval(ZXCVBN_SOURCE)
    end
  end

  def zxcvbn(password)
    @ctx.eval("result = exports.zxcvbn('#{password}')")
    results = ATTRIBUTES.inject({}) do |hash, attribute|
      hash[attribute] = @ctx.eval("result.#{attribute}")
      hash
    end
    results
  end
end

password_strength = PasswordStrength.new
results = password_strength.zxcvbn(password)

results.each do |name, value|
  puts "#{name}: #{value}"
end

# $ ruby zxcvbn.rb 'correct horse battery staple'
# Testing password: correct horse battery staple
# 
# entropy: 62.86
# crack_time: 418398182281428.56
# crack_time_display: centuries
# score: 4
# calc_time: 3