merge

Author: samber

README.md

@@ -127,6 +127,16 @@ Methods:
 - `.Map()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.Map)
 - `.MapNone()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.MapNone)
 - `.FlatMap()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.FlatMap)
+- `.MarshalJSON()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.MarshalJSON)
+- `.UnmarshalJSON()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.UnmarshalJSON)
+- `.MarshalText()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.MarshalText)
+- `.UnmarshalText()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.UnmarshalText)
+- `.MarshalBinary()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.MarshalBinary)
+- `.UnmarshalBinary()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.UnmarshalBinary)
+- `.GobEncode()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.GobEncode)
+- `.GobDecode()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.GobDecode)
+- `.Scan()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.Scan)
+- `.Value()` [doc](https://pkg.go.dev/github.com/samber/mo#Option.Value)
 
 ### Result[T any]
 

option.go

@@ -1,8 +1,14 @@
 package mo
 
 import (
+	"bytes"
+	"database/sql/driver"
+	"encoding/gob"
+	"encoding/json"
+	"errors"
 	"fmt"
 	"reflect"
+	"time"
 )
 
 var optionNoSuchElement = fmt.Errorf("no such element")
@@ -141,3 +147,115 @@ func (o Option[T]) FlatMap(mapper func(value T) Option[T]) Option[T] {
 
 	return None[T]()
 }
+
+// MarshalJSON encodes Option into json.
+func (o Option[T]) MarshalJSON() ([]byte, error) {
+	if o.isPresent {
+		return json.Marshal(o.value)
+	}
+	return json.Marshal(nil)
+}
+
+// UnmarshalJSON decodes Option from json.
+func (o *Option[T]) UnmarshalJSON(b []byte) error {
+	if bytes.Equal(b, []byte("null")) {
+		o.isPresent = false
+		return nil
+	}
+
+	err := json.Unmarshal(b, &o.value)
+	if err != nil {
+		return err
+	}
+
+	o.isPresent = true
+	time.Now()
+	return nil
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+func (o Option[T]) MarshalText() ([]byte, error) {
+	return json.Marshal(o)
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+func (o *Option[T]) UnmarshalText(data []byte) error {
+	return json.Unmarshal(data, o)
+}
+
+// BinaryMarshaler is the interface implemented by an object that can marshal itself into a binary form.
+func (o Option[T]) MarshalBinary() ([]byte, error) {
+	if !o.isPresent {
+		return []byte{0}, nil
+	}
+
+	var buf bytes.Buffer
+
+	enc := gob.NewEncoder(&buf)
+	if err := enc.Encode(o.value); err != nil {
+		return []byte{}, err
+	}
+
+	return append([]byte{1}, buf.Bytes()...), nil
+}
+
+// BinaryUnmarshaler is the interface implemented by an object that can unmarshal a binary representation of itself.
+func (o *Option[T]) UnmarshalBinary(data []byte) error {
+	if len(data) == 0 {
+		return errors.New("Option[T].UnmarshalBinary: no data")
+	}
+
+	if data[0] == 0 {
+		o.isPresent = false
+		o.value = empty[T]()
+		return nil
+	}
+
+	buf := bytes.NewBuffer(data[1:])
+	dec := gob.NewDecoder(buf)
+	err := dec.Decode(&o.value)
+	if err != nil {
+		return err
+	}
+
+	o.isPresent = true
+	return nil
+}
+
+// GobEncode implements the gob.GobEncoder interface.
+func (o Option[T]) GobEncode() ([]byte, error) {
+	return o.MarshalBinary()
+}
+
+// GobDecode implements the gob.GobDecoder interface.
+func (o *Option[T]) GobDecode(data []byte) error {
+	return o.UnmarshalBinary(data)
+}
+
+// Scan implements the SQL driver.Scanner interface.
+func (o *Option[T]) Scan(src any) error {
+	if src == nil {
+		o.isPresent = false
+		o.value = empty[T]()
+		return nil
+	}
+
+	if av, err := driver.DefaultParameterConverter.ConvertValue(src); err == nil {
+		if v, ok := av.(T); ok {
+			o.isPresent = true
+			o.value = v
+			return nil
+		}
+	}
+
+	return fmt.Errorf("failed to scan Option[T]")
+}
+
+// Value implements the driver Valuer interface.
+func (o Option[T]) Value() (driver.Value, error) {
+	if !o.isPresent {
+		return nil, nil
+	}
+
+	return o.value, nil
+}

option_example_test.go

@@ -1,6 +1,7 @@
 package mo
 
 import (
+	"encoding/json"
 	"fmt"
 )
 
@@ -280,3 +281,67 @@ func ExampleOption_FlatMap_none() {
 	fmt.Println(result.IsPresent(), result.OrEmpty())
 	// Output: false 0
 }
+
+func ExampleOption_MarshalJSON_some() {
+	type test struct {
+		Email Option[string] `json:"email"`
+	}
+
+	value := test{Email: Some("samuel@example.com")}
+	result, err := json.Marshal(value)
+
+	fmt.Println(string(result))
+	fmt.Println(err)
+	// Output:
+	// {"email":"samuel@example.com"}
+	// <nil>
+}
+
+func ExampleOption_MarshalJSON_none() {
+	type test struct {
+		Email Option[string] `json:"email"`
+	}
+
+	value := test{Email: None[string]()}
+	result, err := json.Marshal(value)
+
+	fmt.Println(string(result))
+	fmt.Println(err)
+	// Output:
+	// {"email":null}
+	// <nil>
+}
+
+func ExampleOption_UnmarshalJSON_some() {
+	type test struct {
+		Email Option[string] `json:"email"`
+	}
+
+	value := []byte(`{"email":"samuel@example.com"}`)
+
+	var result test
+	err := json.Unmarshal(value, &result)
+
+	fmt.Println(result.Email.Get())
+	fmt.Println(err)
+	// Output:
+	// samuel@example.com true
+	// <nil>
+}
+
+func ExampleOption_UnmarshalJSON_none() {
+	type test struct {
+		Email Option[string] `json:"email"`
+	}
+
+	value := []byte(`{"email":null}`)
+
+	var result test
+	err := json.Unmarshal(value, &result)
+
+	fmt.Println(result.Email.Get())
+	fmt.Println(err)
+	// Output:
+	// false
+	// <nil>
+}