lib/cistern/hash.rb
# frozen_string_literal: true
class Cistern::Hash
# @example
# Cistern::Hash.slice({ :a => 1, :b => 2 }, :a) #=> { :a => 1 }
# @return [Hash] copy of {#hash} containing only {#keys}
def self.slice(hash, *keys)
keys.each_with_object({}) { |e, a| a[e] = hash[e] if hash.key?(e) }
end
# @example
# Cistern::Hash.except({ :a => 1, :b => 2 }, :a) #=> { :b => 2 }
# @return [Hash] copy of {#hash} containing all keys except {#keys}
def self.except(hash, *keys)
Cistern::Hash.except!(hash.dup, *keys)
end
# Remove all keys not specified in {#keys} from {#hash} in place
#
# @example
# Cistern::Hash.except({ :a => 1, :b => 2 }, :a) #=> { :b => 2 }
# @return [Hash] {#hash}
# @see {Cistern::Hash#except}
def self.except!(hash, *keys)
keys.each { |key| hash.delete(key) }
hash
end
# Copy {#hash} and convert all keys to strings recursively.
#
# @example
# Cistern::Hash.stringify_keys(:a => 1, :b => 2) #=> { 'a' => 1, 'b' => 2 }
# @return [Hash] {#hash} with string keys
def self.stringify_keys(object)
case object
when Hash
object.each_with_object({}) { |(k, v), a| a[k.to_s] = stringify_keys(v) }
when Array
object.map { |v| stringify_keys(v) }
else
object
end
end
end