Hey, thank you for writing a good article! What do you think about this small improvement?

Update: In Go, if there is an error the main result is undefined and could be nil, but if there was no error the result should always be valid, even if it's empty.

In my opinion you should never return Unknown if there's an error.

Hi @m110 --

Thought this probably the best way to raise some feedback on your safer enums post & code. The article does not mention serialisation of enums (e.g. to/from JSON, etc). Your recommended struct pattern has a drawback here in that with private members any serialisation will convert the value back to its sentinel zero value.

While the safety of serialising enum without explicit custom marshalling functions is debatable, other enum options like an simple int do serialise OK by default so think it's an angle that would be worth calling out.

Current test was a duplicate of the one above, re-testing the first user instead of the one freshly pulled by ID.

Tests still passing:

⇒ make test
PASS
ok  	github.com/ThreeDotsLabs/go-web-app-antipatterns/tests	0.226s

I continue to write here coming from the post's comment.

I think it's a great idea to use functions because I can reduce the code noticeably having even more security (because I don't use simple strings anymore).

type StateEnum struct {
 	slug string
 }
 
-func (o StateEnum) Is(s string) bool {
-	return o.slug == s
+func (o StateEnum) Is(s StateEnum) bool {
+	return o == s
 }
 
 func (o StateEnum) String() string {
 	return o.slug
 }
 
-const (
-	Draft     = "DRAFT"
-	Completed = "COMPLETED"
-	Approved  = "APPROVED"
-	Rejected  = "REJECTED"
-)
-
-func NewStateEnumFromString(s string) StateEnum {
-	switch s {
-	case Draft:
-		return StateEnum{Draft}
-	case Completed:
-		return StateEnum{Completed}
-	case Approved:
-		return StateEnum{Approved}
-	case Rejected:
-		return StateEnum{Rejected}
-	default:
-		panic("unknown StateEnum")
-	}
-}
+func Draft() StateEnum     { return StateEnum{"DRAFT"} }
+func Completed() StateEnum { return StateEnum{"COMPLETED"} }
+func Approved() StateEnum  { return StateEnum{"APPROVED"} }
+func Rejected() StateEnum  { return StateEnum{"REJECTED"} }

But, there is a but.

In some parts of my codebase I need to marshal and unmarshal from string.

So I need again the func NewStateEnumFromString(), right?