dashboard/paginator (#518)

Author: GeorgeGorbanev

lib/split/dashboard.rb

@@ -3,6 +3,7 @@
 require 'split'
 require 'bigdecimal'
 require 'split/dashboard/helpers'
+require 'split/dashboard/pagination_helpers'
 
 module Split
   class Dashboard < Sinatra::Base
@@ -14,6 +15,7 @@ class Dashboard < Sinatra::Base
     set :method_override, true
 
     helpers Split::DashboardHelpers
+    helpers Split::DashboardPaginationHelpers
 
     get '/' do
       # Display experiments without a winner at the top of the dashboard

lib/split/dashboard/pagination_helpers.rb

@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+require 'split/dashboard/paginator'
+
+module Split
+  module DashboardPaginationHelpers
+    DEFAULT_PER = 10
+
+    def pagination_per
+      @pagination_per ||= (params[:per] || DEFAULT_PER).to_i
+    end
+
+    def page_number
+      @page_number ||= (params[:page] || 1).to_i
+    end
+
+    def paginated(collection)
+      Split::DashboardPaginator.new(collection, page_number, pagination_per).paginate
+    end
+
+    def pagination(collection)
+      html = []
+      html << first_page_tag if show_first_page_tag?
+      html << ellipsis_tag if show_first_ellipsis_tag?
+      html << prev_page_tag if show_prev_page_tag?
+      html << current_page_tag
+      html << next_page_tag if show_next_page_tag?(collection)
+      html << ellipsis_tag if show_last_ellipsis_tag?(collection)
+      html << last_page_tagcollection if show_last_page_tag?(collection)
+      html.join
+    end
+
+    private
+
+    def show_first_page_tag?
+      page_number > 2
+    end
+
+    def first_page_tag
+      %Q(<a href="#{url.chop}?page=1&per=#{pagination_per}">1</a>)
+    end
+
+    def show_first_ellipsis_tag?
+      page_number >= 4
+    end
+
+    def ellipsis_tag
+      '<span>...</span>'
+    end
+
+    def show_prev_page_tag?
+      page_number > 1
+    end
+
+    def prev_page_tag
+      %Q(<a href="#{url.chop}?page=#{page_number - 1}&per=#{pagination_per}">#{page_number - 1}</a>)
+    end
+
+    def current_page_tag
+      "<span><b>#{page_number}</b></span>"
+    end
+
+    def show_next_page_tag?(collection)
+      (page_number * pagination_per) < collection.count
+    end
+
+    def next_page_tag
+      %Q(<a href="#{url.chop}?page=#{page_number + 1}&per=#{pagination_per}">#{page_number + 1}</a>)
+    end
+
+    def show_last_ellipsis_tag?(collection)
+      (total_pages(collection) - page_number) >= 3
+    end
+
+    def total_pages(collection)
+      collection.count / pagination_per + ((collection.count % pagination_per).zero? ? 0 : 1)
+    end
+
+    def show_last_page_tag?(collection)
+      page_number < (total_pages(collection) - 1)
+    end
+
+    def last_page_tag(collection)
+      total = total_pages(collection)
+      %Q(<a href="#{url.chop}?page=#{total}&per=#{pagination_per}">#{total}</a>)
+    end
+  end
+end

lib/split/dashboard/paginator.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+module Split
+  class DashboardPaginator
+    def initialize(collection, page_number, per)
+      @collection = collection
+      @page_number = page_number
+      @per = per
+    end
+
+    def paginate
+      to = @page_number * @per
+      from = to - @per
+      @collection[from...to]
+    end
+  end
+end

lib/split/dashboard/public/style.css

@@ -317,3 +317,12 @@ a.button.green:focus, button.green:focus, input[type="submit"].green:focus {
 }
 
 
+.pagination {
+  text-align: center;
+  font-size: 15px;
+}
+
+.pagination a, .paginaton span {
+  display: inline-block;
+  padding: 5px;
+}

lib/split/dashboard/views/index.erb

@@ -6,7 +6,7 @@
   <input type="button" id="toggle-active" value="Hide active" />
   <input type="button" id="clear-filter" value="Clear filters" />
 
-  <% @experiments.each do |experiment| %>
+  <% paginated(@experiments).each do |experiment| %>
     <% if experiment.goals.empty? %>
       <%= erb :_experiment, :locals => {:goal => nil, :experiment => experiment} %>
     <% else %>
@@ -16,6 +16,10 @@
       <% end %>
     <% end %>
   <% end %>
+
+  <div class="pagination">
+    <%= pagination(@experiments) %>
+  </div>
 <% else %>
   <p class="intro">No experiments have started yet, you need to define them in your code and introduce them to your users.</p>
   <p class="intro">Check out the <a href='https://github.com/splitrb/split#readme'>Readme</a> for more help getting started.</p>

spec/dashboard/pagination_helpers_spec.rb

@@ -0,0 +1,198 @@
+require 'spec_helper'
+require 'split/dashboard/pagination_helpers'
+
+describe Split::DashboardPaginationHelpers do
+  include Split::DashboardPaginationHelpers
+
+  let(:url) { '/split/' }
+
+  describe '#pagination_per' do
+    context 'when params empty' do
+      let(:params) { Hash[] }
+
+      it 'returns 10' do
+        expect(pagination_per).to eql 10
+      end
+    end
+
+    context 'when params[:per] is 5' do
+      let(:params) { Hash[per: 5] }
+
+      it 'returns 5' do
+        expect(pagination_per).to eql 5
+      end
+    end
+  end
+
+  describe '#page_number' do
+    context 'when params empty' do
+      let(:params) { Hash[] }
+
+      it 'returns 1' do
+        expect(page_number).to eql 1
+      end
+    end
+
+    context 'when params[:page] is "2"' do
+      let(:params) { Hash[page: '2'] }
+
+      it 'returns 2' do
+        expect(page_number).to eql 2
+      end
+    end
+  end
+
+  describe '#paginated' do
+    let(:collection) { (1..20).to_a }
+    let(:params) { Hash[per: '5', page: '3'] }
+
+    it { expect(paginated(collection)).to eql [11, 12, 13, 14, 15] }
+  end
+
+  describe '#show_first_page_tag?' do
+    context 'when page is 1' do
+      it { expect(show_first_page_tag?).to be false }
+    end
+
+    context 'when page is 3' do
+      let(:params) { Hash[page: '3'] }
+      it { expect(show_first_page_tag?).to be true }
+    end
+  end
+
+  describe '#first_page_tag' do
+    it { expect(first_page_tag).to eql '<a href="/split?page=1&per=10">1</a>' }
+  end
+
+  describe '#show_first_ellipsis_tag?' do
+    context 'when page is 1' do
+      it { expect(show_first_ellipsis_tag?).to be false }
+    end
+
+    context 'when page is 4' do
+      let(:params) { Hash[page: '4'] }
+      it { expect(show_first_ellipsis_tag?).to be true }
+    end
+  end
+
+  describe '#ellipsis_tag' do
+    it { expect(ellipsis_tag).to eql '<span>...</span>' }
+  end
+
+  describe '#show_prev_page_tag?' do
+    context 'when page is 1' do
+      it { expect(show_prev_page_tag?).to be false }
+    end
+
+    context 'when page is 2' do
+      let(:params) { Hash[page: '2'] }
+      it { expect(show_prev_page_tag?).to be true }
+    end
+  end
+
+  describe '#prev_page_tag' do
+    context 'when page is 2' do
+      let(:params) { Hash[page: '2'] }
+
+      it do
+        expect(prev_page_tag).to eql '<a href="/split?page=1&per=10">1</a>'
+      end
+    end
+
+    context 'when page is 3' do
+      let(:params) { Hash[page: '3'] }
+
+      it do
+        expect(prev_page_tag).to eql '<a href="/split?page=2&per=10">2</a>'
+      end
+    end
+  end
+
+  describe '#show_prev_page_tag?' do
+    context 'when page is 1' do
+      it { expect(show_prev_page_tag?).to be false }
+    end
+
+    context 'when page is 2' do
+      let(:params) { Hash[page: '2'] }
+      it { expect(show_prev_page_tag?).to be true }
+    end
+  end
+
+  describe '#current_page_tag' do
+    context 'when page is 1' do
+      let(:params) { Hash[page: '1'] }
+      it { expect(current_page_tag).to eql '<span><b>1</b></span>' }
+    end
+
+    context 'when page is 2' do
+      let(:params) { Hash[page: '2'] }
+      it { expect(current_page_tag).to eql '<span><b>2</b></span>' }
+    end
+  end
+
+  describe '#show_next_page_tag?' do
+    context 'when page is 2' do
+      let(:params) { Hash[page: '2'] }
+
+      context 'when collection length is 20' do
+        let(:collection) { (1..20).to_a }
+        it { expect(show_next_page_tag?(collection)).to be false }
+      end
+
+      context 'when collection length is 25' do
+        let(:collection) { (1..25).to_a }
+        it { expect(show_next_page_tag?(collection)).to be true }
+      end
+    end
+  end
+
+  describe '#next_page_tag' do
+    context 'when page is 1' do
+      let(:params) { Hash[page: '1'] }
+      it { expect(next_page_tag).to eql '<a href="/split?page=2&per=10">2</a>' }
+    end
+
+    context 'when page is 2' do
+      let(:params) { Hash[page: '2'] }
+      it { expect(next_page_tag).to eql '<a href="/split?page=3&per=10">3</a>' }
+    end
+  end
+
+  describe '#total_pages' do
+    context 'when collection length is 30' do
+      let(:collection) { (1..30).to_a }
+      it { expect(total_pages(collection)).to eql 3 }
+    end
+
+    context 'when collection length is 35' do
+      let(:collection) { (1..35).to_a }
+      it { expect(total_pages(collection)).to eql 4 }
+    end
+  end
+
+  describe '#show_last_ellipsis_tag?' do
+    let(:collection) { (1..30).to_a }
+    let(:params) { Hash[per: '5', page: '2'] }
+    it { expect(show_last_ellipsis_tag?(collection)).to be true }
+  end
+
+  describe '#show_last_page_tag?' do
+    let(:collection) { (1..30).to_a }
+
+    context 'when page is 5/6' do
+      let(:params) { Hash[per: '5', page: '5'] }
+      it { expect(show_last_page_tag?(collection)).to be false }
+    end
+
+    context 'when page is 4/6' do
+      let(:params) { Hash[per: '5', page: '4'] }
+      it { expect(show_last_page_tag?(collection)).to be true }
+    end
+  end
+
+  describe '#last_page_tag' do
+    let(:collection) { (1..30).to_a }
+    it { expect(last_page_tag(collection)).to eql '<a href="/split?page=3&per=10">3</a>' }
+  end
+end

spec/dashboard/paginator_spec.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+require 'spec_helper'
+require 'split/dashboard/paginator'
+
+describe Split::DashboardPaginator do
+  context 'when collection is 1..20' do
+    let(:collection) { (1..20).to_a }
+
+    context 'when per 5 for page' do
+      let(:per) { 5 }
+
+      it 'when page number is 1 result is [1, 2, 3, 4, 5]' do
+        result = Split::DashboardPaginator.new(collection, 1, per).paginate
+        expect(result).to eql [1, 2, 3, 4, 5]
+      end
+
+      it 'when page number is 2 result is [6, 7, 8, 9, 10]' do
+        result = Split::DashboardPaginator.new(collection, 2, per).paginate
+        expect(result).to eql [6, 7, 8, 9, 10]
+      end
+    end
+
+    context 'when per 10 for page' do
+      let(:per) { 10 }
+
+      it 'when page number is 1 result is [1..10]' do
+        result = Split::DashboardPaginator.new(collection, 1, per).paginate
+        expect(result).to eql [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+      end
+
+      it 'when page number is 2 result is [10..20]' do
+        result = Split::DashboardPaginator.new(collection, 2, per).paginate
+        expect(result).to eql [11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
+      end
+    end
+  end
+end