Constraint for object key

[neon oracle]

In the following code sample, x can't be assigned because TKey could be instantiated with an arbitrary type... etc. What would be the best way to resolve this?

https://www.typescriptlang.org/play?jsx=0#code/C4TwDgpgBASg9gdwCrmgXigcgM7AE4CWAdgOaZQA+WRArgLYBGEe5VmDccANhAIZGYAUIIgAPMHDzAooSFACyvYgGE4RAGYESAHiQBpCCChjgEIgBNsUXIVIA+KBhh9zariG3OAxpPO6DIAA0sIgokHZ2ANzCYhJSUD5EuFBwDABWEF7AAVYYusaiphZWqRlZdgAUpQBcUEgAlLV4Lm5GFQDWhnDqdfUA2gC6jnaCUFAA8umZwAB0nSDYVen1ULxWHV09DYPRgonJJHCOUP6GBUWW1vjEJMFIiipqmiTnZpcPRKoaWqcgERVedQkWr3JSfJ5aFZoBwAb1GYwSamS81yKSmWRyAKB9V2CMRSWkoigIICxxRfQADANogBfIA

[idle pawn]

@neon oracle Here's a shortened URL of your playground link! You can remove the full link from your message.

evan.trimboli#6544

Playground Link

Preview:```ts
type RowType = "string" | "number" | "boolean"

export type MainConfig<TKey extends string> = Readonly<
Record<TKey, RowType>

export const objectKeys = <T extends object>(
obj: T
): readonly (keyof T)[] =>
Object.keys(obj) as (keyof T)[]

const go = <
TKey extends string,
TMainConfig extends MainConfig<TKey>

(
cfg: TMainConfig
...```

You can choose specific lines to embed by selecting them before copying the link.

[fierce charm]

It really depends on what your function is actually doing.

Without knowing that, my best answer would be to just remove the key generic.

[idle pawn]

Burrito#6903

Playground Link

Preview:```ts
type RowType = "string" | "number" | "boolean"

export type MainConfig<TKey extends string> = Readonly<
Record<TKey, RowType>

export const objectKeys = <T extends object>(
obj: T
): readonly (keyof T)[] =>
Object.keys(obj) as (keyof T)[]

const go = <TMainConfig extends MainConfig<string>>(
cfg: TMainConf
...```

You can choose specific lines to embed by selecting them before copying the link.

[thick cedar]

It can work if you pass your generic TKey to the objectKeys function