lib/wrest/hash_with_indifferent_access.rb
# frozen_string_literal: true
module Wrest
# https://github.com/rails/rails/commit/1dcad65f8075d5b766082d3fbabdcb20fecb4ccd
# Implements a hash where keys <tt>:foo</tt> and <tt>"foo"</tt> are considered
# to be the same.
#
# rgb = ActiveSupport::HashWithIndifferentAccess.new
#
# rgb[:black] = '#000000'
# rgb[:black] # => '#000000'
# rgb['black'] # => '#000000'
#
# rgb['white'] = '#FFFFFF'
# rgb[:white] # => '#FFFFFF'
# rgb['white'] # => '#FFFFFF'
#
# Internally symbols are mapped to strings when used as keys in the entire
# writing interface (calling <tt>[]=</tt>, <tt>merge</tt>, etc). This
# mapping belongs to the public interface. For example, given:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)
#
# You are guaranteed that the key is returned as a string:
#
# hash.keys # => ["a"]
#
# Technically other types of keys are accepted:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new(a: 1)
# hash[0] = 0
# hash # => {"a"=>1, 0=>0}
#
# but this class is intended for use cases where strings or symbols are the
# expected keys and it is convenient to understand both as the same. For
# example the +params+ hash in Ruby on Rails.
#
# Note that core extensions define <tt>Hash#with_indifferent_access</tt>:
#
# rgb = { black: '#000000', white: '#FFFFFF' }.with_indifferent_access
#
# which may be handy.
#
class HashWithIndifferentAccess < Hash
# Returns +true+ so that <tt>Array#extract_options!</tt> finds members of
# this class.
def extractable_options?
true
end
def with_indifferent_access
dup
end
def nested_under_indifferent_access
self
end
def initialize(constructor = nil)
if constructor.respond_to?(:to_hash)
super()
update(constructor)
hash = constructor.is_a?(Hash) ? constructor : constructor.to_hash
self.default = hash.default if hash.default
self.default_proc = hash.default_proc if hash.default_proc
elsif constructor.nil?
super()
else
super(constructor)
end
end
def self.[](*args)
new.merge!(Hash[*args])
end
alias regular_writer []= unless method_defined?(:regular_writer)
alias regular_update update unless method_defined?(:regular_update)
# Assigns a new value to the hash:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new
# hash[:key] = 'value'
#
# This value can be later fetched using either +:key+ or <tt>'key'</tt>.
def []=(key, value)
regular_writer(convert_key(key), convert_value(value, conversion: :assignment))
end
alias store []=
# Updates the receiver in-place, merging in the hashes passed as arguments:
#
# hash_1 = ActiveSupport::HashWithIndifferentAccess.new
# hash_1[:key] = 'value'
#
# hash_2 = ActiveSupport::HashWithIndifferentAccess.new
# hash_2[:key] = 'New Value!'
#
# hash_1.update(hash_2) # => {"key"=>"New Value!"}
#
# hash = ActiveSupport::HashWithIndifferentAccess.new
# hash.update({ "a" => 1 }, { "b" => 2 }) # => { "a" => 1, "b" => 2 }
#
# The arguments can be either an
# <tt>ActiveSupport::HashWithIndifferentAccess</tt> or a regular +Hash+.
# In either case the merge respects the semantics of indifferent access.
#
# If the argument is a regular hash with keys +:key+ and <tt>"key"</tt> only one
# of the values end up in the receiver, but which one is unspecified.
#
# When given a block, the value for duplicated keys will be determined
# by the result of invoking the block with the duplicated key, the value
# in the receiver, and the value in +other_hash+. The rules for duplicated
# keys follow the semantics of indifferent access:
#
# hash_1[:key] = 10
# hash_2['key'] = 12
# hash_1.update(hash_2) { |key, old, new| old + new } # => {"key"=>22}
def update(*other_hashes, &block)
if other_hashes.size == 1
update_with_single_argument(other_hashes.first, block)
else
other_hashes.each do |other_hash|
update_with_single_argument(other_hash, block)
end
end
self
end
alias merge! update
# Checks the hash for a key matching the argument passed in:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new
# hash['key'] = 'value'
# hash.key?(:key) # => true
# hash.key?('key') # => true
def key?(key)
super(convert_key(key))
end
alias include? key?
alias has_key? key?
alias member? key?
# Same as <tt>Hash#[]</tt> where the key passed as argument can be
# either a string or a symbol:
#
# counters = ActiveSupport::HashWithIndifferentAccess.new
# counters[:foo] = 1
#
# counters['foo'] # => 1
# counters[:foo] # => 1
# counters[:zoo] # => nil
def [](key)
super(convert_key(key))
end
# Same as <tt>Hash#assoc</tt> where the key passed as argument can be
# either a string or a symbol:
#
# counters = ActiveSupport::HashWithIndifferentAccess.new
# counters[:foo] = 1
#
# counters.assoc('foo') # => ["foo", 1]
# counters.assoc(:foo) # => ["foo", 1]
# counters.assoc(:zoo) # => nil
def assoc(key)
super(convert_key(key))
end
# Same as <tt>Hash#fetch</tt> where the key passed as argument can be
# either a string or a symbol:
#
# counters = ActiveSupport::HashWithIndifferentAccess.new
# counters[:foo] = 1
#
# counters.fetch('foo') # => 1
# counters.fetch(:bar, 0) # => 0
# counters.fetch(:bar) { |key| 0 } # => 0
# counters.fetch(:zoo) # => KeyError: key not found: "zoo"
def fetch(key, *extras)
super(convert_key(key), *extras)
end
# Same as <tt>Hash#dig</tt> where the key passed as argument can be
# either a string or a symbol:
#
# counters = ActiveSupport::HashWithIndifferentAccess.new
# counters[:foo] = { bar: 1 }
#
# counters.dig('foo', 'bar') # => 1
# counters.dig(:foo, :bar) # => 1
# counters.dig(:zoo) # => nil
def dig(*args)
args[0] = convert_key(args[0]) if args.size.positive?
super(*args)
end
# Same as <tt>Hash#default</tt> where the key passed as argument can be
# either a string or a symbol:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new(1)
# hash.default # => 1
#
# hash = ActiveSupport::HashWithIndifferentAccess.new { |hash, key| key }
# hash.default # => nil
# hash.default('foo') # => 'foo'
# hash.default(:foo) # => 'foo'
def default(*args)
super(*args.map { |arg| convert_key(arg) })
end
# Returns an array of the values at the specified indices:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new
# hash[:a] = 'x'
# hash[:b] = 'y'
# hash.values_at('a', 'b') # => ["x", "y"]
def values_at(*keys)
super(*keys.map { |key| convert_key(key) })
end
# Returns an array of the values at the specified indices, but also
# raises an exception when one of the keys can't be found.
#
# hash = ActiveSupport::HashWithIndifferentAccess.new
# hash[:a] = 'x'
# hash[:b] = 'y'
# hash.fetch_values('a', 'b') # => ["x", "y"]
# hash.fetch_values('a', 'c') { |key| 'z' } # => ["x", "z"]
# hash.fetch_values('a', 'c') # => KeyError: key not found: "c"
def fetch_values(*indices, &block)
super(*indices.map { |key| convert_key(key) }, &block)
end
# Returns a shallow copy of the hash.
#
# hash = ActiveSupport::HashWithIndifferentAccess.new({ a: { b: 'b' } })
# dup = hash.dup
# dup[:a][:c] = 'c'
#
# hash[:a][:c] # => "c"
# dup[:a][:c] # => "c"
def dup
self.class.new(self).tap do |new_hash|
set_defaults(new_hash)
end
end
# This method has the same semantics of +update+, except it does not
# modify the receiver but rather returns a new hash with indifferent
# access with the result of the merge.
def merge(*hashes, &block)
dup.update(*hashes, &block)
end
# Like +merge+ but the other way around: Merges the receiver into the
# argument and returns a new hash with indifferent access as result:
#
# hash = ActiveSupport::HashWithIndifferentAccess.new
# hash['a'] = nil
# hash.reverse_merge(a: 0, b: 1) # => {"a"=>nil, "b"=>1}
def reverse_merge(other_hash)
super(self.class.new(other_hash))
end
alias with_defaults reverse_merge
# Same semantics as +reverse_merge+ but modifies the receiver in-place.
def reverse_merge!(other_hash)
super(self.class.new(other_hash))
end
alias with_defaults! reverse_merge!
# Replaces the contents of this hash with other_hash.
#
# h = { "a" => 100, "b" => 200 }
# h.replace({ "c" => 300, "d" => 400 }) # => {"c"=>300, "d"=>400}
def replace(other_hash)
super(self.class.new(other_hash))
end
# Removes the specified key from the hash.
def delete(key)
super(convert_key(key))
end
# Returns a hash with indifferent access that includes everything except given keys.
# hash = { a: "x", b: "y", c: 10 }.with_indifferent_access
# hash.except(:a, "b") # => {c: 10}.with_indifferent_access
# hash # => { a: "x", b: "y", c: 10 }.with_indifferent_access
def except(*keys)
slice(*self.keys - keys.map { |key| convert_key(key) })
end
alias without except
def stringify_keys!
transform_keys!(&:to_s)
end
def stringify_keys
transform_keys(&:to_s)
end
def symbolize_keys
symbolize_keys!
end
def symbolize_keys!
transform_keys! do |key|
key.to_sym
rescue StandardError
key
end
end
alias to_options symbolize_keys
def to_options!
self
end
def select(*args, &block)
return to_enum(:select) unless block_given?
dup.tap { |hash| hash.select!(*args, &block) }
end
def reject(*args, &block)
return to_enum(:reject) unless block_given?
dup.tap { |hash| hash.reject!(*args, &block) }
end
def transform_values(*args, &block)
return to_enum(:transform_values) unless block_given?
dup.tap { |hash| hash.transform_values!(*args, &block) }
end
def transform_keys(*args, &block)
return to_enum(:transform_keys) unless block_given?
dup.tap { |hash| hash.transform_keys!(*args, &block) }
end
def transform_keys!
return enum_for(:transform_keys!) { size } unless block_given?
keys.each do |key|
self[yield(key)] = delete(key)
end
self
end
def slice(*keys)
keys.map! { |key| convert_key(key) }
self.class.new(super)
end
def slice!(*keys)
keys.map! { |key| convert_key(key) }
super
end
def compact
dup.tap(&:compact!)
end
# Convert to a regular hash with string keys.
def to_hash
a_new_hash = {}
set_defaults(a_new_hash)
each do |key, value|
a_new_hash[key] = convert_value(value, conversion: :to_hash)
end
a_new_hash
end
private
if Symbol.method_defined?(:name)
def convert_key(key)
key.is_a?(Symbol) ? key.name : key
end
else
def convert_key(key)
key.is_a?(Symbol) ? key.to_s : key
end
end
def convert_value(value, conversion: nil)
case value
when Hash
convert_hash_value(conversion, value)
when Array
convert_array_value(conversion, value)
else
value
end
end
def convert_array_value(conversion, value)
value = value.dup if conversion != :assignment || value.frozen?
value.map! { |e| convert_value(e, conversion: conversion) }
value
end
def convert_hash_value(conversion, value)
if conversion == :to_hash
value.to_hash
else
HashWithIndifferentAccess.new(value)
end
end
def set_defaults(target) # rubocop:disable Naming/AccessorMethodName
if default_proc
target.default_proc = default_proc.dup
else
target.default = default
end
end
def update_with_single_argument(other_hash, block)
if other_hash.is_a? HashWithIndifferentAccess
regular_update(other_hash, &block)
else
other_hash.to_hash.each_pair do |key, value|
value = block.call(convert_key(key), self[key], value) if block && key?(key)
regular_writer(convert_key(key), convert_value(value))
end
end
end
end
end