1 files changed, 8 insertions, 5 deletions
diff --git a/activesupport/lib/active_support/core_ext/hash/compact.rb b/activesupport/lib/active_support/core_ext/hash/compact.rb
index 62ea579c65..f072530e04 100644
--- a/activesupport/lib/active_support/core_ext/hash/compact.rb
+++ b/activesupport/lib/active_support/core_ext/hash/compact.rb
@@ -2,18 +2,21 @@ class Hash
   # Returns a hash with non +nil+ values.
   #
   #   hash = { a: true, b: false, c: nil }
-  #   hash.compact       # => { a: true, b: false }
-  #   hash               # => { a: true, b: false, c: nil }
-  #   { c: nil }.compact # => {}
+  #   hash.compact        # => { a: true, b: false }
+  #   hash                # => { a: true, b: false, c: nil }
+  #   { c: nil }.compact  # => {}
+  #   { c: true }.compact # => { c: true }
   def compact
     self.select { |_, value| !value.nil? }
   end
 
   # Replaces current hash with non +nil+ values.
+  # Returns nil if no changes were made, otherwise returns the hash.
   #
   #   hash = { a: true, b: false, c: nil }
-  #   hash.compact! # => { a: true, b: false }
-  #   hash          # => { a: true, b: false }
+  #   hash.compact!        # => { a: true, b: false }
+  #   hash                 # => { a: true, b: false }
+  #   { c: true }.compact! # => nil
   def compact!
     self.reject! { |_, value| value.nil? }
   end