Extracted String#truncate from TextHelper#truncate [DHH]

1 files changed, 33 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/string/filters.rb b/activesupport/lib/active_support/core_ext/string/filters.rb
index 6fda7efef5..cdd86a836f 100644
--- a/activesupport/lib/active_support/core_ext/string/filters.rb
+++ b/activesupport/lib/active_support/core_ext/string/filters.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/string/multibyte'
+
 class String
   # Returns the string, first removing all whitespace on both ends of
   # the string, and then changing remaining consecutive whitespace
@@ -17,4 +19,35 @@ class String
     gsub!(/\s+/, ' ')
     self
   end
+
+  # Truncates a given +text+ after a given <tt>length</tt> if +text+ is longer than <tt>length</tt>.
+  # The last characters will be replaced with the <tt>:omission</tt> (defaults to "...")
+  # for a total length not exceeding <tt>:length</tt>.
+  #
+  # Pass a <tt>:separator</tt> to truncate +text+ at a natural break.
+  #
+  # ==== Examples
+  #
+  #   "Once upon a time in a world far far away".truncate(30)
+  #   # => Once upon a time in a worl...
+  #
+  #   "Once upon a time in a world far far away".truncate(30, :separator => ' ')
+  #   # => Once upon a time in a world...
+  #
+  #   "Once upon a time in a world far far away".truncate(14)
+  #   # => Once upon a...
+  #
+  #   "And they found that many people were sleeping better.".truncate(25, :omission => "... (continued)")
+  #   # => And they f... (continued)
+  def truncate(length, options = {})
+    text = self.dup
+    options[:omission] ||= "..."
+
+    length_with_room_for_omission = length - options[:omission].mb_chars.length
+    chars = text.mb_chars
+    stop = options[:separator] ?
+      (chars.rindex(options[:separator].mb_chars, length_with_room_for_omission) || length_with_room_for_omission) : length_with_room_for_omission
+
+    (chars.length > length ? chars[0...stop] + options[:omission] : text).to_s
+  end
 end