activesupport/lib/active_support/core_ext/enumerable.rb
# frozen_string_literal: true
module ActiveSupport
module EnumerableCoreExt # :nodoc:
module Constants
private
def const_missing(name)
if name == :SoleItemExpectedError
::ActiveSupport::EnumerableCoreExt::SoleItemExpectedError
else
super
end
end
end
end
end
module Enumerable
# Error generated by +sole+ when called on an enumerable that doesn't have
# exactly one item.
class SoleItemExpectedError < StandardError; end
# HACK: For performance reasons, Enumerable shouldn't have any constants of its own.
# So we move SoleItemExpectedError into ActiveSupport::EnumerableCoreExt.
ActiveSupport::EnumerableCoreExt::SoleItemExpectedError = remove_const(:SoleItemExpectedError)
singleton_class.prepend(ActiveSupport::EnumerableCoreExt::Constants)
# Calculates the minimum from the extracted elements.
#
# payments = [Payment.new(5), Payment.new(15), Payment.new(10)]
# payments.minimum(:price) # => 5
def minimum(key)
map(&key).min
end
# Calculates the maximum from the extracted elements.
#
# payments = [Payment.new(5), Payment.new(15), Payment.new(10)]
# payments.maximum(:price) # => 15
def maximum(key)
map(&key).max
end
# Convert an enumerable to a hash, using the block result as the key and the
# element as the 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
if block_given?
result = {}
each { |elem| result[yield(elem)] = elem }
result
else
to_enum(:index_by) { size if respond_to?(:size) }
end
end
# Convert an enumerable to a hash, using the element as the key and the block
# result as the value.
#
# 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?" }
#
# If an argument is passed instead of a block, it will be used as the value
# for all elements:
#
# %i( created_at updated_at ).index_with(Time.now)
# # => { created_at: 2020-03-09 22:31:47, updated_at: 2020-03-09 22:31:47 }
def index_with(default = (no_default = true))
if block_given?
result = {}
each { |elem| result[elem] = yield(elem) }
result
elsif no_default
to_enum(:index_with) { size if respond_to?(:size) }
else
result = {}
each { |elem| result[elem] = default }
result
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+
# if more than one person is over 26.
def many?
cnt = 0
if block_given?
any? do |*args|
cnt += 1 if yield(*args)
cnt > 1
end
else
any? { (cnt += 1) > 1 }
end
end
# Returns a new array that includes the passed elements.
#
# [ 1, 2, 3 ].including(4, 5)
# # => [ 1, 2, 3, 4, 5 ]
#
# ["David", "Rafael"].including %w[ Aaron Todd ]
# # => ["David", "Rafael", "Aaron", "Todd"]
def including(*elements)
to_a.including(*elements)
end
# The negative of the <tt>Enumerable#include?</tt>. Returns +true+ if the
# collection does not include the object.
def exclude?(object)
!include?(object)
end
# Returns a copy of the enumerable excluding the specified elements.
#
# ["David", "Rafael", "Aaron", "Todd"].excluding "Aaron", "Todd"
# # => ["David", "Rafael"]
#
# ["David", "Rafael", "Aaron", "Todd"].excluding %w[ Aaron Todd ]
# # => ["David", "Rafael"]
#
# {foo: 1, bar: 2, baz: 3}.excluding :bar
# # => {foo: 1, baz: 3}
def excluding(*elements)
elements.flatten!(1)
reject { |element| elements.include?(element) }
end
alias :without :excluding
# Extract the given key from each element in the enumerable.
#
# [{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pluck(:name)
# # => ["David", "Rafael", "Aaron"]
#
# [{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pluck(:id, :name)
# # => [[1, "David"], [2, "Rafael"]]
def pluck(*keys)
if keys.many?
map { |element| keys.map { |key| element[key] } }
else
key = keys.first
map { |element| element[key] }
end
end
# Extract the given key from the first element in the enumerable.
#
# [{ name: "David" }, { name: "Rafael" }, { name: "Aaron" }].pick(:name)
# # => "David"
#
# [{ id: 1, name: "David" }, { id: 2, name: "Rafael" }].pick(:id, :name)
# # => [1, "David"]
def pick(*keys)
return if none?
if keys.many?
keys.map { |key| first[key] }
else
first[keys.first]
end
end
# Returns a new +Array+ without the blank items.
# Uses Object#blank? for determining if an item is blank.
#
# [1, "", nil, 2, " ", [], {}, false, true].compact_blank
# # => [1, 2, true]
#
# Set.new([nil, "", 1, false]).compact_blank
# # => [1]
#
# When called on a +Hash+, returns a new +Hash+ without the blank values.
#
# { a: "", b: 1, c: nil, d: [], e: false, f: true }.compact_blank
# # => { b: 1, f: true }
def compact_blank
reject(&:blank?)
end
# Returns a new +Array+ where the order has been set to that provided in the +series+, based on the +key+ of the
# objects in the original enumerable.
#
# [ Person.find(5), Person.find(3), Person.find(1) ].in_order_of(:id, [ 1, 5, 3 ])
# # => [ Person.find(1), Person.find(5), Person.find(3) ]
#
# If the +series+ include keys that have no corresponding element in the Enumerable, these are ignored.
# If the Enumerable has additional elements that aren't named in the +series+, these are not included in the result.
def in_order_of(key, series)
group_by(&key).values_at(*series).flatten(1).compact
end
# Returns the sole item in the enumerable. If there are no items, or more
# than one item, raises +Enumerable::SoleItemExpectedError+.
#
# ["x"].sole # => "x"
# Set.new.sole # => Enumerable::SoleItemExpectedError: no item found
# { a: 1, b: 2 }.sole # => Enumerable::SoleItemExpectedError: multiple items found
def sole
case count
when 1 then return first # rubocop:disable Style/RedundantReturn
when 0 then raise ActiveSupport::EnumerableCoreExt::SoleItemExpectedError, "no item found"
when 2.. then raise ActiveSupport::EnumerableCoreExt::SoleItemExpectedError, "multiple items found"
end
end
end
class Hash
# Hash#reject has its own definition, so this needs one too.
def compact_blank # :nodoc:
reject { |_k, v| v.blank? }
end
# Removes all blank values from the +Hash+ in place and returns self.
# Uses Object#blank? for determining if a value is blank.
#
# h = { a: "", b: 1, c: nil, d: [], e: false, f: true }
# h.compact_blank!
# # => { b: 1, f: true }
def compact_blank!
# use delete_if rather than reject! because it always returns self even if nothing changed
delete_if { |_k, v| v.blank? }
end
end
class Range # :nodoc:
# Optimize range sum to use arithmetic progression if a block is not given and
# we have a range of numeric values.
def sum(initial_value = 0)
if block_given? || !(first.is_a?(Integer) && last.is_a?(Integer))
super
else
actual_last = exclude_end? ? (last - 1) : last
if actual_last >= first
sum = initial_value || 0
sum + (actual_last - first + 1) * (actual_last + first) / 2
else
initial_value || 0
end
end
end
end
class Array # :nodoc:
# Removes all blank elements from the +Array+ in place and returns self.
# Uses Object#blank? for determining if an item is blank.
#
# a = [1, "", nil, 2, " ", [], {}, false, true]
# a.compact_blank!
# # => [1, 2, true]
def compact_blank!
# use delete_if rather than reject! because it always returns self even if nothing changed
delete_if(&:blank?)
end
end