Enum const members set to -0 get compiled into 0

[CraigMacomber]

🔎 Search Terms

enum constant minus-zero -0

🕗 Version & Regression Information

• This is the behavior in every version I tried ( 3.3.3 - 5.9.0-dev.20250702 )

⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.9.0-dev.20250702#code/KYOwrgtgBAGlDeAoKKoBkCWAXYAnAhgDZQC8UAtAAyIC+iiAxgPYgDOThwAdIUwOYAKAPIAjAFbAGWLhlYCYXTDgKEANBUoBKTQG5EQA

💻 Code

enum X {
    Literal = -0
}

console.log(Object.is(X.Literal, -0));

🙁 Actual behavior

Generates

"use strict";
var X;
(function (X) {
    X[X["Literal"] = 0] = "Literal";
})(X || (X = {}));
console.log(Object.is(X.Literal, -0));

🙂 Expected behavior

Either Generates an enum member with a value of -0, or an error.

"use strict";
var X;
(function (X) {
    X[X["Literal"] = -0] = "Literal";
})(X || (X = {}));
console.log(Object.is(X.Literal, -0));

Additional information about the issue

The reverse mappings in this case might be problematic since both 0 and -1 stringify to 0. That said, TypeScript is already ok with multiple entries that have the same value overwriting the reverse mapping (and even the enum entries themselves in the case of infinites and NaN) so I think it would be fine. That issue though is why it might be desirable to error.

[MartinJohns]

Duplicate of #55093.