feat: Introduce simple HashSerializer (#19)

lib/typed/hash_serializer.rb

@@ -0,0 +1,25 @@
+# typed: strict
+
+module Typed
+  class HashSerializer < Serializer
+    Input = type_member { {fixed: T::Hash[T.any(Symbol, String), T.untyped]} }
+    Output = type_member { {fixed: T::Hash[Symbol, T.untyped]} }
+
+    sig { override.params(source: Input).returns(Result[T::Struct, DeserializeError]) }
+    def deserialize(source)
+      deserialize_from_creation_params(symbolize_keys(source))
+    end
+
+    sig { override.params(struct: T::Struct).returns(Output) }
+    def serialize(struct)
+      symbolize_keys(struct.serialize)
+    end
+
+    private
+
+    sig { params(hash: T::Hash[T.any(String, Symbol), T.untyped]).returns(T::Hash[Symbol, T.untyped]) }
+    def symbolize_keys(hash)
+      hash.each_with_object({}) { |(k, v), h| h[k.intern] = v }
+    end
+  end
+end

lib/typed/json_serializer.rb

@@ -4,31 +4,23 @@
 
 module Typed
   class JSONSerializer < Serializer
-    extend T::Sig
+    Input = type_member { {fixed: String} }
+    Output = type_member { {fixed: String} }
 
-    sig { override.params(source: String).returns(Result[T::Struct, DeserializeError]) }
+    sig { override.params(source: Input).returns(Result[T::Struct, DeserializeError]) }
     def deserialize(source)
       parsed_json = JSON.parse(source)
 
       creation_params = schema.fields.each_with_object(T.let({}, Params)) do |field, hsh|
         hsh[field.name] = parsed_json[field.name.to_s]
       end
 
-      results = creation_params.map do |name, value|
-        schema.field(name:)&.validate(value)
-      end.compact
-
-      Validations::ValidationResults
-        .new(results:)
-        .combine
-        .and_then do
-          Success.new(schema.target.new(**creation_params))
-        end
+      deserialize_from_creation_params(creation_params)
     rescue JSON::ParserError
       Failure.new(ParseError.new(format: :json))
     end
 
-    sig { override.params(struct: T::Struct).returns(String) }
+    sig { override.params(struct: T::Struct).returns(Output) }
     def serialize(struct)
       JSON.generate(struct.serialize)
     end

lib/typed/schema.rb

@@ -2,16 +2,9 @@
 
 module Typed
   class Schema < T::Struct
-    extend T::Sig
-
     include T::Struct::ActsAsComparable
 
     const :fields, T::Array[Field], default: []
     const :target, T.class_of(T::Struct)
-
-    sig { params(name: Symbol).returns(T.nilable(Field)) }
-    def field(name:)
-      fields.find { |field| field.name == name }
-    end
   end
 end

lib/typed/serializer.rb

@@ -4,9 +4,13 @@ module Typed
   class Serializer
     extend T::Sig
     extend T::Helpers
+    extend T::Generic
     abstract!
 
+    Input = type_member
+    Output = type_member
     Params = T.type_alias { T::Hash[Symbol, T.untyped] }
+    DeserializeResult = T.type_alias { Typed::Result[T::Struct, DeserializeError] }
 
     sig { returns(Schema) }
     attr_reader :schema
@@ -16,12 +20,28 @@ def initialize(schema:)
       @schema = schema
     end
 
-    sig { abstract.params(source: String).returns(Typed::Result[T::Struct, DeserializeError]) }
+    sig { abstract.params(source: Output).returns(DeserializeResult) }
     def deserialize(source)
     end
 
-    sig { abstract.params(struct: T::Struct).returns(String) }
+    sig { abstract.params(struct: T::Struct).returns(Output) }
     def serialize(struct)
     end
+
+    private
+
+    sig { params(creation_params: Params).returns(DeserializeResult) }
+    def deserialize_from_creation_params(creation_params)
+      results = schema.fields.map do |field|
+        field.validate(creation_params[field.name])
+      end
+
+      Validations::ValidationResults
+        .new(results:)
+        .combine
+        .and_then do
+          Success.new(schema.target.new(**creation_params))
+        end
+    end
   end
 end

test/struct_ext_test.rb

@@ -1,7 +1,5 @@
 # typed: true
 
-require "sorbet-schema/struct_ext"
-
 class StructExtTest < Minitest::Test
   def test_create_schema_is_available
     assert_equal(PersonSchema, Person.create_schema)

test/test_helper.rb

@@ -10,5 +10,6 @@
 require "debug"
 
 require "sorbet-schema"
+require "sorbet-schema/struct_ext"
 
 require_relative "support/schemas/person_schema"

test/typed/hash_serializer_test.rb

@@ -0,0 +1,59 @@
+# typed: true
+
+class HashSerializerTest < Minitest::Test
+  def setup
+    @serializer = Typed::HashSerializer.new(schema: PersonSchema)
+  end
+
+  # Serialize Tests
+
+  def test_it_can_simple_serialize
+    max = PersonSchema.target.new(name: "Max", age: 29)
+
+    assert_equal({name: "Max", age: 29}, @serializer.serialize(max))
+  end
+
+  # Deserialize Tests
+
+  def test_it_can_simple_deserialize
+    max_hash = {name: "Max", age: 29}
+
+    result = @serializer.deserialize(max_hash)
+
+    assert_success(result)
+    assert_payload(PersonSchema.target.new(name: "Max", age: 29), result)
+  end
+
+  def test_it_can_simple_deserialize_from_string_keys
+    max_hash = {"name" => "Max", "age" => 29}
+
+    result = @serializer.deserialize(max_hash)
+
+    assert_success(result)
+    assert_payload(PersonSchema.target.new(name: "Max", age: 29), result)
+  end
+
+  def test_it_reports_validation_errors_on_deserialize
+    max_hash = {name: "Max"}
+
+    result = @serializer.deserialize(max_hash)
+
+    assert_failure(result)
+    assert_error(Typed::Validations::RequiredFieldError.new(field_name: :age), result)
+  end
+
+  def test_it_reports_multiple_validation_errors_on_deserialize
+    result = @serializer.deserialize({})
+
+    assert_failure(result)
+    assert_error(
+      Typed::Validations::MultipleValidationError.new(
+        errors: [
+          Typed::Validations::RequiredFieldError.new(field_name: :name),
+          Typed::Validations::RequiredFieldError.new(field_name: :age)
+        ]
+      ),
+      result
+    )
+  end
+end