Find the followers in common between two Twitter users

followers_in_common

#!/usr/bin/env ruby

# Usage:
# ./followers_in_common maxholder sandimetz

# You'll need to `gem install twitter`
require 'twitter'

# see: https://dev.twitter.com/oauth/overview/application-owner-access-tokens
client = Twitter::REST::Client.new do |config|
  config.consumer_key        = "CONSUMER_KEY"
  config.consumer_secret     = "CONSUMER_SECRET"
  config.access_token        = "ACCESS_TOKEN"
  config.access_token_secret = "ACCESS_SECRET"
end

screen_name1 = ARGV.shift
screen_name2 = ARGV.shift

client.users(
  [screen_name1, screen_name2]
    .map { |screen_name| client.follower_ids(screen_name).to_a }
    .reduce(:&)
)
  .map { |user| [user.screen_name, user.name ] }
  .map { |screen_name, name| puts "#{screen_name.ljust(20)}#{name}" }