Value collisions in string enums result in contradictory typings

[LoeschMaximilian]

🔎 Search Terms

"enum"

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about Enums

⏯ Playground Link

https://www.typescriptlang.org/play?#code/FAUwdgrgtgBAsiAzoghgcyTA3sGeYASAogDIkDyMAvDAEQBGAniLcAL6iSwLLqY74YAIQCaRanSYt2wAMYB7MIgAuMWRJ6oMiAHSiiAbmBA

💻 Code

enum Messages {
    HELLO = "bye"
}
enum Messages {
    BYE = "bye"
}
const c = Messages.BYE;

🙁 Actual behavior

declarations

declare enum Messages {
    HELLO = "bye"
}
declare enum Messages {
    BYE = "bye"
}
declare const c = Messages.HELLO;

🙂 Expected behavior

declarations

declare enum Messages {
    HELLO = "bye"
}
declare enum Messages {
    BYE = "bye"
}
declare const c = Messages.BYE;

Additional information about the issue

I was experimenting with using a global enum to differentiate messages from a message broker like the BroadcastChannel browser API. I was hoping to get compile-errors when a string enum gets expanded by a key with an already present value. It makes sense, that there is no error at compile-time, but the result should at least be consistent between the JavaScript and .d.ts results.

The idea relates to #53013

[RyanCavanaugh]

This behavior is still correct; the values are considered interchangeable and are effectively aliases for each other.

// Not an error
const c: Messages.HELLO = Messages.BYE;

[typescript-bot]

This issue has been marked as "Not a Defect" and has seen no recent activity. It has been automatically closed for house-keeping purposes.