Object.values on an enum with template literal values

[Hacksore]

Repro: https://github.com/Hacksore/test-ts-objects-literals

This only happens with esbuild and when you use template literal values.

I can't repro on tsplayground

repro code

const staticMember = "static";

enum TemplateLiteral {
  Minecraft = `minecraft_${staticMember}`,
  Lol = `lol_${staticMember}`,
}

console.log(Object.values(TemplateLiteral);

expected

[ 'minecraft_static', 'lol_static' ]

actual

[ 'minecraft_static', 'Minecraft', 'lol_static', 'Lol' ]

[evanw]

TypeScript's rule for this is the backward mapping is only omitted if the initializer is a string literal, which is also the rule that esbuild implements. I think the issue here is that esbuild doesn't necessarily inline constants in the exact same situations that TypeScript does, which affects whether the initializer is a string or not.

The general solution here isn't for esbuild to replicate TypeScript's behavior exactly because that's impossible (TypeScript's behavior for this may involve type information, for example with the inlining of declare const, and esbuild deliberately doesn't emulate TypeScript's type system).

I think in this case esbuild could potentially consider a template literal initializer to be the same as a string literal. Then esbuild would mostly match TypeScript's behavior (except in the case where TypeScript can't inline the string, but then TypeScript emits a compile error so esbuild's behavior doesn't really matter in that case).

[Hacksore]

My workaround for is migrating back to ts-node instead of using tsx.

@evanw if you do fix this let me know but at least this issue is here for others who encounter the behaviour.

Closing for now.

[evanw]

I plan to apply the fix that I described above.