Add uncolor method

lib/rainbow/global.rb

@@ -12,6 +12,10 @@ def self.enabled
   def self.enabled=(value)
     global.enabled = value
   end
+
+  def self.uncolor(string)
+    StringUtils.uncolor(string)
+  end
 end
 
 def Rainbow(string)

lib/rainbow/string_utils.rb

@@ -12,5 +12,10 @@ def self.wrap_with_sgr(string, codes)
 
       string
     end
+
+    def self.uncolor(string)
+      # See http://www.commandlinefu.com/commands/view/3584/remove-color-codes-special-characters-with-sed
+      string.gsub(/\e\[[0-9;]*?m/, '')
+    end
   end
 end

spec/integration/uncolor_spec.rb

@@ -0,0 +1,14 @@
+require 'spec_helper'
+require 'rainbow'
+
+describe 'uncolor method' do
+
+  it 'strips ansi color escape code' do
+    expect(Rainbow.uncolor("\e[35mhello\e[0mm")).to eq 'hellom'
+  end
+
+  it 'does not strip scroll down escape code' do
+    expect(Rainbow.uncolor("\e[1Thello")).to eq "\e[1Thello"
+  end
+
+end

spec/unit/string_utils_spec.rb

@@ -56,5 +56,39 @@ class Stringgg < ::String; end
         end
       end
     end
+
+    describe '.uncolor' do
+      subject { described_class.uncolor(string) }
+
+      context "when string with ansi color escape is passed" do
+        let(:string) do
+          rainbow = Rainbow.new
+          rainbow.enabled = true
+          rainbow.wrap('hello').
+            foreground(:red).
+            bright.
+            bold.
+            italic.
+            background('#ff8040').
+            underline.
+            color(:blue).
+            blink.
+            inverse.
+            hide
+        end
+
+        it "removes ansi color codes" do
+          expect(subject).to eq 'hello'
+        end
+      end
+
+      context "when string with scroll down ansi escape is passed" do
+        let(:string) { "\e[1Thello" }
+
+        it "does not remove ansi scroll down escape" do
+          expect(subject).to eq "\e[1Thello"
+        end
+      end
+    end
   end
 end