Refactoring ideas for https://github.com/JamesChevalier/hashtagged/blob/master/app.rb#L17-L27. Extract an object. Encapsulate the interaction with the Twitter client. Extract named methods for looping logic.

app.rb

require 'sinatra'
require 'twitter'

class App < Sinatra::Base
  get '/' do
    erb :index
  end
  
  post '/hashtags' do
    @user_name = user_name
    @hashtags = HashtagAggregator.new(user_name, twitter_client).hashtags
  
    erb :hashtags
  end

  private 
  
  def user_name
    params[:user_name]
  end
  
  def twitter_client
    Twitter::REST::Client.new do |config|
      config.consumer_key        = ENV['TWITTER_CONSUMER_KEY']
      config.consumer_secret     = ENV['TWITTER_CONSUMER_SECRET']
      config.access_token        = ENV['TWITTER_ACCESS_TOKEN']
      config.access_token_secret = ENV['TWITTER_ACCESS_TOKEN_SECRET']
    end
  end
end

hashtag_aggregator.rb

class HashtagAggregator
  def initialize(user_name, client)
    @user_name = user_name
    @client = client
  end
  
  def hashtags
    hashtag_list.uniq.map do |tag|
      { 
        text: tag,
        weight: hashtag_list.count(tag),
        link: { href: TwitterSearch.url_for(tag), target: '_blank', title: tag }
      }
    end
  end

  private
  
  attr_reader :user_name, :client
  
  def hashtag_list
    @hashtag_list ||= tweets.map{ |tweet| tweet.hashtags.map(&:text) }.flatten
  end
  
  def tweets
    client.user_timeline(user_name, { count: 200, include_entities: true })
  end
end

hashtag_aggregator_spec.rb

requrie 'spec_helper'

describe HastagAggregator, '#hashtags' do
  let(:tag_text) { 'baxter' }
  
  it 'returns an array of unique hashtags' do
    user_name = 'RonBurgundy'
    
    result = HastagAggregator.new(user_name, stubbed_client).hash_tags
    
    expect(result).to eq(
      [
        {
          text: tag_text,
          weight: 1,
          link: { href: TwitterSearch.url_for(tag_text), target: '_blank', title: tag_text }
        }
      ]
    )
  end
  
  def stubbed_client
    hashtag = double(text: tag_text)
    tweet = double(hashtags: [hashtag])
    client = double(user_timeline: [tweet])
  end
end

twitter_search.rb

class TwitterSearch
  SEARCH_URL = 'https://twitter.com/search?q=%23'
  
  def self.url_for(search_term)
    "#{SEARCH_URL}#{search_term}"
  end
end