types.rb

require 'dry-struct'
require 'dry-initializer'

module Types
  include Dry::Types.module

  class ExtHash < ::Hash
    def self.from_hash(hsh)
      new.merge! hsh
    end

    def compact
      self.class.new.merge!(to_h.select { |_, v| v })
    end

    def hyphenate_keys
      hsh = each_with_object({}) do |(k, v), memo|
        memo[k.to_s.tr('_', '-').to_sym] = v
      end
      self.class.new.merge!(hsh)
    end

    def deep_merge(second)
      merger = proc { |key, v1, v2| Hash === v1 && Hash === v2 ? v1.merge(v2, &merger) : v2 }
      self.merge(second, &merger)
    end
  end

  class SafeStruct < Dry::Struct
    constructor_type :safe_with_defaults
  end
end

# dry-types issue 194
module Dry
  module Types
    class Hash
      class SafeWithDefaults < StrictWithDefaults
        private
        def resolve(hash)
          sub = sub_hash(symbolize_keys(hash), member_types.keys)
          super(sub)
        end

        def sub_hash(hash, keys)
          keys = keys.select { |k| hash.key?(k) }
          ::Hash[keys.zip(hash.values_at(*keys))]
        end

        def symbolize_keys(hash)
          hash.inject({}) { |memo, (k, v)|
            memo[k.to_sym] = v
            memo
          }
        end
      end

      def safe_with_defaults(type_map)
        schema(type_map, SafeWithDefaults)
      end
    end
  end
end