diff options
Diffstat (limited to 'activesupport/lib/active_support/core_ext/enumerable.rb')
-rw-r--r-- | activesupport/lib/active_support/core_ext/enumerable.rb | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/activesupport/lib/active_support/core_ext/enumerable.rb b/activesupport/lib/active_support/core_ext/enumerable.rb index edde4f46b9..d87d63f287 100644 --- a/activesupport/lib/active_support/core_ext/enumerable.rb +++ b/activesupport/lib/active_support/core_ext/enumerable.rb @@ -1,14 +1,21 @@ # frozen_string_literal: true module Enumerable + INDEX_WITH_DEFAULT = Object.new + private_constant :INDEX_WITH_DEFAULT + # Enumerable#sum was added in Ruby 2.4, but it only works with Numeric elements # when we omit an identity. + # :stopdoc: + # We can't use Refinements here because Refinements with Module which will be prepended # doesn't work well https://bugs.ruby-lang.org/issues/13446 - alias :_original_sum_with_required_identity :sum # :nodoc: + alias :_original_sum_with_required_identity :sum private :_original_sum_with_required_identity + # :startdoc: + # Calculates a sum from the elements. # # payments.sum { |p| p.price * p.tax_rate } @@ -37,10 +44,11 @@ module Enumerable end end - # Convert an enumerable to a hash. + # Convert an enumerable to a hash keying it by the block return value. # # people.index_by(&:login) # # => { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...} + # # people.index_by { |person| "#{person.first_name} #{person.last_name}" } # # => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...} def index_by @@ -53,6 +61,26 @@ module Enumerable end end + # Convert an enumerable to a hash keying it with the enumerable items and with the values returned in the block. + # + # post = Post.new(title: "hey there", body: "what's up?") + # + # %i( title body ).index_with { |attr_name| post.public_send(attr_name) } + # # => { title: "hey there", body: "what's up?" } + def index_with(default = INDEX_WITH_DEFAULT) + if block_given? + result = {} + each { |elem| result[elem] = yield(elem) } + result + elsif default != INDEX_WITH_DEFAULT + result = {} + each { |elem| result[elem] = default } + result + else + to_enum(:index_with) { size if respond_to?(:size) } + end + end + # Returns +true+ if the enumerable has more than 1 element. Functionally # equivalent to <tt>enum.to_a.size > 1</tt>. Can be called with a block too, # much like any?, so <tt>people.many? { |p| p.age > 26 }</tt> returns +true+ |