How to preserve stirng union inside of an object

[abstract saddle]

autumnlight#0

Playground Link

Preview:```ts
class Extension<T extends string> {
name: T
constructor(args: T) {
this.name = args
}
}

const g = new Extension("f")
g.name
// ^?

class _Extension<T extends {test: string}> {
name: T
constructor(args: T) {
this.name = args
}
}

const g2 = new _Extension({test: "f"})
...```

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[round tartan]

g.name is "f"
but g2 is string

[gray pumice]

Strings inside objects are inferred as the string type instead of the specific string literal
You can get it to infer the string literal using const T extends {test: string}

[round tartan]

you saved my day

Thank you @gray pumice

[gray pumice]

You're welcome
Please !close the thread if you have no follow-up questions