From d90d141c24228b8df6333b03d26a1723480837ba Mon Sep 17 00:00:00 2001
From: Tony Rom <thetonyrom@gmail.com>
Date: Wed, 20 Dec 2017 14:39:40 +0300
Subject: [PATCH 1/2] Add Colors to GitLab Flavored Markdown

---
 app/assets/javascripts/gfm_auto_complete.js   |  2 +-
 app/assets/stylesheets/framework/gfm.scss     | 30 +++++++
 changelogs/unreleased/24167__color_label.yml  |  5 ++
 doc/user/markdown.md                          | 41 ++++++++-
 lib/banzai/color_parser.rb                    | 50 +++++++++++
 lib/banzai/filter/color_filter.rb             | 31 +++++++
 .../pipeline/broadcast_message_pipeline.rb    |  1 +
 lib/banzai/pipeline/gfm_pipeline.rb           |  1 +
 spec/features/markdown_spec.rb                |  8 ++
 spec/fixtures/markdown.md.erb                 | 12 +++
 spec/javascripts/gfm_auto_complete_spec.js    |  9 ++
 spec/lib/banzai/color_parser_spec.rb          | 90 +++++++++++++++++++
 spec/lib/banzai/filter/color_filter_spec.rb   | 61 +++++++++++++
 spec/support/matchers/markdown_matchers.rb    | 21 +++++
 14 files changed, 360 insertions(+), 2 deletions(-)
 create mode 100644 changelogs/unreleased/24167__color_label.yml
 create mode 100644 lib/banzai/color_parser.rb
 create mode 100644 lib/banzai/filter/color_filter.rb
 create mode 100644 spec/lib/banzai/color_parser_spec.rb
 create mode 100644 spec/lib/banzai/filter/color_filter_spec.rb

diff --git a/app/assets/javascripts/gfm_auto_complete.js b/app/assets/javascripts/gfm_auto_complete.js
index df20e1e9c88..57a1fa107e5 100644
--- a/app/assets/javascripts/gfm_auto_complete.js
+++ b/app/assets/javascripts/gfm_auto_complete.js
@@ -461,7 +461,7 @@ class GfmAutoComplete {
     const accentAChar = decodeURI('%C3%80');
     const accentYChar = decodeURI('%C3%BF');
 
-    const regexp = new RegExp(`^(?:\\B|[^a-zA-Z0-9_${atSymbolsWithoutBar}]|\\s)${resultantFlag}(?!${atSymbolsWithBar})((?:[A-Za-z${accentAChar}-${accentYChar}0-9_'.+-]|[^\\x00-\\x7a])*)$`, 'gi');
+    const regexp = new RegExp(`^(?:\\B|[^a-zA-Z0-9_\`${atSymbolsWithoutBar}]|\\s)${resultantFlag}(?!${atSymbolsWithBar})((?:[A-Za-z${accentAChar}-${accentYChar}0-9_'.+-]|[^\\x00-\\x7a])*)$`, 'gi');
 
     return regexp.exec(targetSubtext);
   }
diff --git a/app/assets/stylesheets/framework/gfm.scss b/app/assets/stylesheets/framework/gfm.scss
index 5621505996d..6eff57157cc 100644
--- a/app/assets/stylesheets/framework/gfm.scss
+++ b/app/assets/stylesheets/framework/gfm.scss
@@ -16,3 +16,33 @@
     background-color: $user-mention-bg-hover;
   }
 }
+
+.gfm-color_chip {
+  display: inline-block;
+  margin-left: 4px;
+  margin-bottom: 2px;
+  vertical-align: middle;
+  border-radius: 3px;
+
+  $side: 0.9em;
+  $bg-size: $side / 0.9;
+  $bg-pos: $bg-size / 2;
+  $bg-color: $gray-dark;
+
+  width: $side;
+  height: $side;
+  background: $white-light;
+  background-image: linear-gradient(135deg, $bg-color 25%, transparent 0%, transparent 75%, $bg-color 0%),
+                    linear-gradient(135deg, $bg-color 25%, transparent 0%, transparent 75%, $bg-color 0%);
+  background-size: $bg-size $bg-size;
+  background-position: 0 0, $bg-pos $bg-pos;
+
+  > span {
+    display: inline-block;
+    width: 100%;
+    height: 100%;
+    margin-bottom: 2px;
+    border-radius: 3px;
+    border: 1px solid $black-transparent;
+  }
+}
diff --git a/changelogs/unreleased/24167__color_label.yml b/changelogs/unreleased/24167__color_label.yml
new file mode 100644
index 00000000000..68c6c731163
--- /dev/null
+++ b/changelogs/unreleased/24167__color_label.yml
@@ -0,0 +1,5 @@
+---
+title: Add Colors to GitLab Flavored Markdown
+merge_request: 16095
+author: Tony Rom <thetonyrom@gmail.com>
+type: added
diff --git a/doc/user/markdown.md b/doc/user/markdown.md
index 552abac747b..b590dfa0d40 100644
--- a/doc/user/markdown.md
+++ b/doc/user/markdown.md
@@ -253,7 +253,7 @@ GFM will recognize the following:
 | `@user_name`               | specific user                   |
 | `@group_name`              | specific group                  |
 | `@all`                     | entire team                     |
-| `#123`                     | issue                           |
+| `#12345`                   | issue                           |
 | `!123`                     | merge request                   |
 | `$123`                     | snippet                         |
 | `~123`                     | label by ID                     |
@@ -379,6 +379,45 @@ _Be advised that KaTeX only supports a [subset][katex-subset] of LaTeX._
 >**Note:**
 This also works for the asciidoctor `:stem: latexmath`. For details see the [asciidoctor user manual][asciidoctor-manual].
 
+### Colors
+
+> If this is not rendered correctly, see
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#colors
+
+It is possible to have color written in HEX, RGB or HSL format rendered with a color indicator.
+
+Color written inside backticks will be followed by a color "chip".
+
+Examples:
+
+    `#F00`
+    `#F00A`
+    `#FF0000`
+    `#FF0000AA`
+    `RGB(0,255,0)`
+    `RGB(0%,100%,0%)`
+    `RGBA(0,255,0,0.7)`
+    `HSL(540,70%,50%)`
+    `HSLA(540,70%,50%,0.7)`
+
+Becomes:
+
+`#F00`  
+`#F00A`  
+`#FF0000`  
+`#FF0000AA`  
+`RGB(0,255,0)`  
+`RGB(0%,100%,0%)`  
+`RGBA(0,255,0,0.7)`  
+`HSL(540,70%,50%)`  
+`HSLA(540,70%,50%,0.7)`  
+
+#### Supported formats:
+
+* HEX: `` `#RGB[A]` `` or `` `#RRGGBB[AA]` ``
+* RGB: `` `RGB[A](R, G, B[, A])` ``
+* HSL: `` `HSL[A](H, S, L[, A])` ``
+
 ### Mermaid
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/15107) in
diff --git a/lib/banzai/color_parser.rb b/lib/banzai/color_parser.rb
new file mode 100644
index 00000000000..d96c0a1ed1f
--- /dev/null
+++ b/lib/banzai/color_parser.rb
@@ -0,0 +1,50 @@
+module Banzai
+  module ColorParser
+    ALPHA = /0(?:\.\d+)?|\.\d+|1(?:\.0+)?/ # 0.0..1.0
+    PERCENTS = /(?:\d{1,2}|100)%/ # 00%..100%
+    ALPHA_CHANNEL = /(?:,\s*(?:#{ALPHA}|#{PERCENTS}))?/
+    BITS = /\d{1,2}|1\d\d|2(?:[0-4]\d|5[0-5])/ # 00..255
+    DEGS = /-?\d+(?:deg)?/i # [-]digits[deg]
+    RADS = /-?(?:\d+(?:\.\d+)?|\.\d+)rad/i # [-](digits[.digits] OR .digits)rad
+    HEX_FORMAT = /\#(?:\h{3}|\h{4}|\h{6}|\h{8})/
+    RGB_FORMAT = /
+      (?:rgba?
+        \(
+          (?:
+            (?:(?:#{BITS},\s*){2}#{BITS})
+            |
+            (?:(?:#{PERCENTS},\s*){2}#{PERCENTS})
+          )
+          #{ALPHA_CHANNEL}
+        \)
+      )
+    /xi
+    HSL_FORMAT = /
+      (?:hsla?
+        \(
+          (?:#{DEGS}|#{RADS}),\s*#{PERCENTS},\s*#{PERCENTS}
+          #{ALPHA_CHANNEL}
+        \)
+      )
+    /xi
+
+    FORMATS = [HEX_FORMAT, RGB_FORMAT, HSL_FORMAT].freeze
+
+    class << self
+      # Public: Analyzes whether the String is a color code.
+      #
+      # text - The String to be parsed.
+      #
+      # Returns the recognized color String or nil if none was found.
+      def parse(text)
+        text if color_format =~ text
+      end
+
+      private
+
+      def color_format
+        @color_format ||= /\A(#{Regexp.union(FORMATS)})\z/ix
+      end
+    end
+  end
+end
diff --git a/lib/banzai/filter/color_filter.rb b/lib/banzai/filter/color_filter.rb
new file mode 100644
index 00000000000..6ab29ac281f
--- /dev/null
+++ b/lib/banzai/filter/color_filter.rb
@@ -0,0 +1,31 @@
+module Banzai
+  module Filter
+    # HTML filter that renders `color` followed by a color "chip".
+    #
+    class ColorFilter < HTML::Pipeline::Filter
+      COLOR_CHIP_CLASS = 'gfm-color_chip'.freeze
+
+      def call
+        doc.css('code').each do |node|
+          color = ColorParser.parse(node.content)
+          node << color_chip(color) if color
+        end
+
+        doc
+      end
+
+      private
+
+      def color_chip(color)
+        checkerboard = doc.document.create_element('span', class: COLOR_CHIP_CLASS)
+        chip = doc.document.create_element('span', style: inline_styles(color: color))
+
+        checkerboard << chip
+      end
+
+      def inline_styles(color:)
+        "background-color: #{color};"
+      end
+    end
+  end
+end
diff --git a/lib/banzai/pipeline/broadcast_message_pipeline.rb b/lib/banzai/pipeline/broadcast_message_pipeline.rb
index adc09c8afbd..5dd572de3a1 100644
--- a/lib/banzai/pipeline/broadcast_message_pipeline.rb
+++ b/lib/banzai/pipeline/broadcast_message_pipeline.rb
@@ -7,6 +7,7 @@ module Banzai
           Filter::SanitizationFilter,
 
           Filter::EmojiFilter,
+          Filter::ColorFilter,
           Filter::AutolinkFilter,
           Filter::ExternalLinkFilter
         ]
diff --git a/lib/banzai/pipeline/gfm_pipeline.rb b/lib/banzai/pipeline/gfm_pipeline.rb
index c746f6f64e9..4001b8a85e3 100644
--- a/lib/banzai/pipeline/gfm_pipeline.rb
+++ b/lib/banzai/pipeline/gfm_pipeline.rb
@@ -14,6 +14,7 @@ module Banzai
           Filter::SyntaxHighlightFilter,
 
           Filter::MathFilter,
+          Filter::ColorFilter,
           Filter::MermaidFilter,
           Filter::VideoLinkFilter,
           Filter::ImageLazyLoadFilter,
diff --git a/spec/features/markdown_spec.rb b/spec/features/markdown_spec.rb
index a2b78a5e021..f13d78d24e3 100644
--- a/spec/features/markdown_spec.rb
+++ b/spec/features/markdown_spec.rb
@@ -259,6 +259,10 @@ describe 'GitLab Markdown' do
     it 'includes VideoLinkFilter' do
       expect(doc).to parse_video_links
     end
+
+    it 'includes ColorFilter' do
+      expect(doc).to parse_colors
+    end
   end
 
   context 'wiki pipeline' do
@@ -320,6 +324,10 @@ describe 'GitLab Markdown' do
     it 'includes VideoLinkFilter' do
       expect(doc).to parse_video_links
     end
+
+    it 'includes ColorFilter' do
+      expect(doc).to parse_colors
+    end
   end
 
   # Fake a `current_user` helper
diff --git a/spec/fixtures/markdown.md.erb b/spec/fixtures/markdown.md.erb
index 71abb6da607..da32a46675f 100644
--- a/spec/fixtures/markdown.md.erb
+++ b/spec/fixtures/markdown.md.erb
@@ -280,6 +280,18 @@ However the wrapping tags cannot be mixed as such:
 
 ![My Video](/assets/videos/gitlab-demo.mp4)
 
+### Colors
+
+`#F00`  
+`#F00A`  
+`#FF0000`  
+`#FF0000AA`  
+`RGB(0,255,0)`  
+`RGB(0%,100%,0%)`  
+`RGBA(0,255,0,0.7)`  
+`HSL(540,70%,50%)`  
+`HSLA(540,70%,50%,0.7)`  
+
 ### Mermaid
 
 > If this is not rendered correctly, see
diff --git a/spec/javascripts/gfm_auto_complete_spec.js b/spec/javascripts/gfm_auto_complete_spec.js
index 6f357306ec7..182880d42e9 100644
--- a/spec/javascripts/gfm_auto_complete_spec.js
+++ b/spec/javascripts/gfm_auto_complete_spec.js
@@ -131,6 +131,7 @@ describe('GfmAutoComplete', function () {
 
     describe('should not match special sequences', () => {
       const ShouldNotBeFollowedBy = flags.concat(['\x00', '\x10', '\x3f', '\n', ' ']);
+      const ShouldNotBePrependedBy = ['`'];
 
       flagsUseDefaultMatcher.forEach((atSign) => {
         ShouldNotBeFollowedBy.forEach((followedSymbol) => {
@@ -140,6 +141,14 @@ describe('GfmAutoComplete', function () {
             expect(defaultMatcher(atwhoInstance, atSign, seq)).toBe(null);
           });
         });
+
+        ShouldNotBePrependedBy.forEach((prependedSymbol) => {
+          const seq = prependedSymbol + atSign;
+
+          it(`should not match "${seq}"`, () => {
+            expect(defaultMatcher(atwhoInstance, atSign, seq)).toBe(null);
+          });
+        });
       });
     });
   });
diff --git a/spec/lib/banzai/color_parser_spec.rb b/spec/lib/banzai/color_parser_spec.rb
new file mode 100644
index 00000000000..a1cb0c07b06
--- /dev/null
+++ b/spec/lib/banzai/color_parser_spec.rb
@@ -0,0 +1,90 @@
+require 'spec_helper'
+
+describe Banzai::ColorParser do
+  describe '.parse' do
+    context 'HEX format' do
+      [
+        '#abc', '#ABC',
+        '#d2d2d2', '#D2D2D2',
+        '#123a', '#123A',
+        '#123456aa', '#123456AA'
+      ].each do |color|
+        it "parses the valid hex color #{color}" do
+          expect(subject.parse(color)).to eq(color)
+        end
+      end
+
+      [
+        '#', '#1', '#12', '#12g', '#12G',
+        '#12345', '#r2r2r2', '#R2R2R2', '#1234567',
+        '# 123', '# 1234', '# 123456', '# 12345678',
+        '#1 2 3', '#123 4', '#12 34 56', '#123456 78'
+      ].each do |color|
+        it "does not parse the invalid hex color #{color}" do
+          expect(subject.parse(color)).to be_nil
+        end
+      end
+    end
+
+    context 'RGB format' do
+      [
+        'rgb(0,0,0)', 'rgb(255,255,255)',
+        'rgb(0, 0, 0)', 'RGB(0,0,0)',
+        'rgb(0,0,0,0)',  'rgb(0,0,0,0.0)',  'rgb(0,0,0,.0)',
+        'rgb(0,0,0, 0)', 'rgb(0,0,0, 0.0)', 'rgb(0,0,0, .0)',
+        'rgb(0,0,0,1)',  'rgb(0,0,0,1.0)',
+        'rgba(0,0,0)', 'rgba(0,0,0,0)', 'RGBA(0,0,0)',
+        'rgb(0%,0%,0%)', 'rgba(0%,0%,0%,0%)'
+      ].each do |color|
+        it "parses the valid rgb color #{color}" do
+          expect(subject.parse(color)).to eq(color)
+        end
+      end
+
+      [
+        'FOOrgb(0,0,0)', 'rgb(0,0,0)BAR',
+        'rgb(0,0,-1)', 'rgb(0,0,-0)', 'rgb(0,0,256)',
+        'rgb(0,0,0,-0.1)', 'rgb(0,0,0,-0.0)', 'rgb(0,0,0,-.1)',
+        'rgb(0,0,0,1.1)',  'rgb(0,0,0,2)',
+        'rgba(0,0,0,)', 'rgba(0,0,0,0.)', 'rgba(0,0,0,1.)',
+        'rgb(0,0,0%)', 'rgb(101%,0%,0%)'
+      ].each do |color|
+        it "does not parse the invalid rgb color #{color}" do
+          expect(subject.parse(color)).to be_nil
+        end
+      end
+    end
+
+    context 'HSL format' do
+      [
+        'hsl(0,0%,0%)',  'hsl(0,100%,100%)',
+        'hsl(540,0%,0%)', 'hsl(-720,0%,0%)',
+        'hsl(0deg,0%,0%)', 'hsl(0DEG,0%,0%)',
+        'hsl(0, 0%, 0%)', 'HSL(0,0%,0%)',
+        'hsl(0,0%,0%,0)', 'hsl(0,0%,0%,0.0)', 'hsl(0,0%,0%,.0)',
+        'hsl(0,0%,0%, 0)', 'hsl(0,0%,0%, 0.0)', 'hsl(0,0%,0%, .0)',
+        'hsl(0,0%,0%,1)', 'hsl(0,0%,0%,1.0)',
+        'hsla(0,0%,0%)', 'hsla(0,0%,0%,0)', 'HSLA(0,0%,0%)',
+        'hsl(1rad,0%,0%)', 'hsl(1.1rad,0%,0%)', 'hsl(.1rad,0%,0%)',
+        'hsl(-1rad,0%,0%)', 'hsl(1RAD,0%,0%)'
+      ].each do |color|
+        it "parses the valid hsl color #{color}" do
+          expect(subject.parse(color)).to eq(color)
+        end
+      end
+
+      [
+        'hsl(+0,0%,0%)', 'hsl(0,0,0%)', 'hsl(0,0%,0)', 'hsl(0 deg,0%,0%)',
+        'hsl(0,-0%,0%)', 'hsl(0,101%,0%)', 'hsl(0,-1%,0%)',
+        'hsl(0,0%,0%,-0.1)', 'hsl(0,0%,0%,-.1)',
+        'hsl(0,0%,0%,1.1)', 'hsl(0,0%,0%,2)',
+        'hsl(0,0%,0%,)', 'hsl(0,0%,0%,0.)', 'hsl(0,0%,0%,1.)',
+        'hsl(deg,0%,0%)', 'hsl(rad,0%,0%)'
+      ].each do |color|
+        it "does not parse the invalid hsl color #{color}" do
+          expect(subject.parse(color)).to be_nil
+        end
+      end
+    end
+  end
+end
diff --git a/spec/lib/banzai/filter/color_filter_spec.rb b/spec/lib/banzai/filter/color_filter_spec.rb
new file mode 100644
index 00000000000..a098b037510
--- /dev/null
+++ b/spec/lib/banzai/filter/color_filter_spec.rb
@@ -0,0 +1,61 @@
+require 'spec_helper'
+
+describe Banzai::Filter::ColorFilter, lib: true do
+  include FilterSpecHelper
+
+  let(:color) { '#F00' }
+  let(:color_chip_selector) { 'code > span.gfm-color_chip > span' }
+
+  ['#123', '#1234', '#123456', '#12345678',
+   'rgb(0,0,0)', 'RGB(0, 0, 0)', 'rgba(0,0,0,1)', 'RGBA(0,0,0,0.7)',
+   'hsl(270,30%,50%)', 'HSLA(270, 30%, 50%, .7)'].each do |color|
+    it "inserts color chip for supported color format #{color}" do
+      content = code_tag(color)
+      doc = filter(content)
+      color_chip = doc.at_css(color_chip_selector)
+
+      expect(color_chip.content).to be_empty
+      expect(color_chip.parent[:class]).to eq 'gfm-color_chip'
+      expect(color_chip[:style]).to eq "background-color: #{color};"
+    end
+  end
+
+  it 'ignores valid color code without backticks(code tags)' do
+    doc = filter(color)
+
+    expect(doc.css('span.gfm-color_chip').size).to be_zero
+  end
+
+  it 'ignores valid color code with prepended space' do
+    content = code_tag(' ' + color)
+    doc = filter(content)
+
+    expect(doc.css(color_chip_selector).size).to be_zero
+  end
+
+  it 'ignores valid color code with appended space' do
+    content = code_tag(color + ' ')
+    doc = filter(content)
+
+    expect(doc.css(color_chip_selector).size).to be_zero
+  end
+
+  it 'ignores valid color code surrounded by spaces' do
+    content = code_tag(' ' + color + ' ')
+    doc = filter(content)
+
+    expect(doc.css(color_chip_selector).size).to be_zero
+  end
+
+  it 'ignores invalid color code' do
+    invalid_color = '#BAR'
+    content = code_tag(invalid_color)
+    doc = filter(content)
+
+    expect(doc.css(color_chip_selector).size).to be_zero
+  end
+
+  def code_tag(string)
+    "<code>#{string}</code>"
+  end
+end
diff --git a/spec/support/matchers/markdown_matchers.rb b/spec/support/matchers/markdown_matchers.rb
index d12b2757427..ec4ec6f4038 100644
--- a/spec/support/matchers/markdown_matchers.rb
+++ b/spec/support/matchers/markdown_matchers.rb
@@ -190,6 +190,27 @@ module MarkdownMatchers
       expect(video['src']).to end_with('/assets/videos/gitlab-demo.mp4')
     end
   end
+
+  # ColorFilter
+  matcher :parse_colors do
+    set_default_markdown_messages
+
+    match do |actual|
+      color_chips = actual.css('code > span.gfm-color_chip > span')
+
+      expect(color_chips.count).to eq(9)
+
+      [
+        '#F00', '#F00A', '#FF0000', '#FF0000AA', 'RGB(0,255,0)',
+        'RGB(0%,100%,0%)', 'RGBA(0,255,0,0.7)', 'HSL(540,70%,50%)',
+        'HSLA(540,70%,50%,0.7)'
+      ].each_with_index do |color, i|
+        parsed_color = Banzai::ColorParser.parse(color)
+        expect(color_chips[i]['style']).to match("background-color: #{parsed_color};")
+        expect(color_chips[i].parent.parent.content).to match(color)
+      end
+    end
+  end
 end
 
 # Monkeypatch the matcher DSL so that we can reduce some noisy duplication for

From 57f8b24fe2d54df4dfcc3ddcb5796e41093f0fd7 Mon Sep 17 00:00:00 2001
From: Tony Rom <thetonyrom@gmail.com>
Date: Thu, 1 Feb 2018 13:35:03 +0300
Subject: [PATCH 2/2] Fix minors

---
 app/assets/stylesheets/framework/gfm.scss  | 16 +++++++---------
 lib/banzai/color_parser.rb                 | 22 ++++++++--------------
 spec/javascripts/gfm_auto_complete_spec.js |  8 ++++----
 3 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/app/assets/stylesheets/framework/gfm.scss b/app/assets/stylesheets/framework/gfm.scss
index 6eff57157cc..e378e84ca1b 100644
--- a/app/assets/stylesheets/framework/gfm.scss
+++ b/app/assets/stylesheets/framework/gfm.scss
@@ -19,21 +19,19 @@
 
 .gfm-color_chip {
   display: inline-block;
-  margin-left: 4px;
-  margin-bottom: 2px;
+  margin: 0 0 2px 4px;
   vertical-align: middle;
   border-radius: 3px;
 
-  $side: 0.9em;
-  $bg-size: $side / 0.9;
+  $chip-size: 0.9em;
+  $bg-size: $chip-size / 0.9;
   $bg-pos: $bg-size / 2;
-  $bg-color: $gray-dark;
 
-  width: $side;
-  height: $side;
+  width: $chip-size;
+  height: $chip-size;
   background: $white-light;
-  background-image: linear-gradient(135deg, $bg-color 25%, transparent 0%, transparent 75%, $bg-color 0%),
-                    linear-gradient(135deg, $bg-color 25%, transparent 0%, transparent 75%, $bg-color 0%);
+  background-image: linear-gradient(135deg, $gray-dark 25%, transparent 0%, transparent 75%, $gray-dark 0%),
+                    linear-gradient(135deg, $gray-dark 25%, transparent 0%, transparent 75%, $gray-dark 0%);
   background-size: $bg-size $bg-size;
   background-position: 0 0, $bg-pos $bg-pos;
 
diff --git a/lib/banzai/color_parser.rb b/lib/banzai/color_parser.rb
index d96c0a1ed1f..0cd9085190c 100644
--- a/lib/banzai/color_parser.rb
+++ b/lib/banzai/color_parser.rb
@@ -30,21 +30,15 @@ module Banzai
 
     FORMATS = [HEX_FORMAT, RGB_FORMAT, HSL_FORMAT].freeze
 
-    class << self
-      # Public: Analyzes whether the String is a color code.
-      #
-      # text - The String to be parsed.
-      #
-      # Returns the recognized color String or nil if none was found.
-      def parse(text)
-        text if color_format =~ text
-      end
+    COLOR_FORMAT = /\A(#{Regexp.union(FORMATS)})\z/ix
 
-      private
-
-      def color_format
-        @color_format ||= /\A(#{Regexp.union(FORMATS)})\z/ix
-      end
+    # Public: Analyzes whether the String is a color code.
+    #
+    # text - The String to be parsed.
+    #
+    # Returns the recognized color String or nil if none was found.
+    def self.parse(text)
+      text if COLOR_FORMAT =~ text
     end
   end
 end
diff --git a/spec/javascripts/gfm_auto_complete_spec.js b/spec/javascripts/gfm_auto_complete_spec.js
index 182880d42e9..50a587ef351 100644
--- a/spec/javascripts/gfm_auto_complete_spec.js
+++ b/spec/javascripts/gfm_auto_complete_spec.js
@@ -130,11 +130,11 @@ describe('GfmAutoComplete', function () {
     });
 
     describe('should not match special sequences', () => {
-      const ShouldNotBeFollowedBy = flags.concat(['\x00', '\x10', '\x3f', '\n', ' ']);
-      const ShouldNotBePrependedBy = ['`'];
+      const shouldNotBeFollowedBy = flags.concat(['\x00', '\x10', '\x3f', '\n', ' ']);
+      const shouldNotBePrependedBy = ['`'];
 
       flagsUseDefaultMatcher.forEach((atSign) => {
-        ShouldNotBeFollowedBy.forEach((followedSymbol) => {
+        shouldNotBeFollowedBy.forEach((followedSymbol) => {
           const seq = atSign + followedSymbol;
 
           it(`should not match "${seq}"`, () => {
@@ -142,7 +142,7 @@ describe('GfmAutoComplete', function () {
           });
         });
 
-        ShouldNotBePrependedBy.forEach((prependedSymbol) => {
+        shouldNotBePrependedBy.forEach((prependedSymbol) => {
           const seq = prependedSymbol + atSign;
 
           it(`should not match "${seq}"`, () => {