faker.helpers.objectKey returns wrong type

[ST-DDT]

Pre-Checks

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• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
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• The provided reproduction is a minimal reproducible example of the bug.
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Describe the bug

When calling faker.helpers.objectKey with a Record<number, *> it declares to return a number, but actually returns a string.

I discovered this, when I tried to pass a mapped type to the function and got string | number back.

const object: { [a: string]: '1' } = { a: '1' };
const value: string = faker.helpers.objectKey(object); // 🧨Cannot assign `number | string` to `string`
console.log(value, typeof value); // a string

Minimal reproduction code

const object: Record<number, number> = { 1: 1 };
const value: number = faker.helpers.objectKey(object);
console.log(value, typeof value); // 1 string

Additional Context

This seems to be intentional on the TypeScript side.
https://stackoverflow.com/questions/51808160/keyof-inferring-string-number-when-key-is-only-a-string

Environment Info

Binaries:
    Node: 20.11.1 - C:\Program Files\nodejs\node.EXE
    pnpm: 8.12.1 - C:\Program Files\nodejs\pnpm.CMD
  npmPackages:
    @faker-js/faker: 8.4.1 => 8.4.1

Which module system do you use?

• CJS
• ESM

Used Package Manager

pnpm

[Shinigami92]

For me it shows this (next-branch):

[ST-DDT]

You have to use a mapped type explicitly as shown in the minimal reproduction code.

And for the later one, if you run console.log(typeof x) then it returns string and not number.

[ST-DDT]

Team Decision

• "This seems to be intentional on the TypeScript side."