Implementing Custom JSON Marshaling for Domain Types

package main
 
import (
	"encoding/json"
	"fmt"
	"strings"
)
 
type Status int
 
const (
	Pending Status = iota
	Active
)
 
func (s Status) MarshalJSON() ([]byte, error) {
	var str string
	switch s {
	case Pending:
		str = "pending"
	case Active:
		str = "active"
	default:
		str = "unknown"
	}
	return json.Marshal(str)
}
 
func (s *Status) UnmarshalJSON(data []byte) error {
	var str string
	if err := json.Unmarshal(data, &str); err != nil {
		return err
	}
	caseInsensitive := strings.ToLower(str)
	switch caseInsensitive {
	case "pending":
		*s = Pending
	case "active":
		*s = Active
	default:
		return fmt.Errorf("invalid status: %s", str)
	}
	return nil
}