fix(within): Add extra type paramater to allow reassigning in TypeScript

[Dennis273]

What:

Closes testing-library/react-testing-library#979

TS error occurs when reassigning the return value of within

import { screen, within } from "@testing-library/dom";
import "@types/jest";
import "@testing-library/jest-dom";

const navigation = screen.getByRole("navigation");
let breadcrumbs = within(navigation);
expect(breadcrumbs.getByRole("link", { name: /home/i })).toBeInTheDocument();
// ts error occurs
breadcrumbs = within(navigation);

https://www.typescriptlang.org/play?#code/JYWwDg9gTgLgBAbzgZwMZQKYYHYBo4DuwMAFsNnAL5wBmUEIcARAAIwbIzkDmAtADbAARlACGUAJ4B6ACYMmAbgBQoSLGZsJYDlIBWHGIpXho8Vu048BwsZL0HeckEaWoI2TnGyiAbsG6iXO5wALwo6FjYAHTcGDAAQhIAShD8GAAUTN5+AUHYTACUymnwIhiiMugAriBCyKGExGTY6dn+gcDuRUoYAB7aqDDpZRXVtcgxcYkpaZmC2ADWTPhI3iAYAFxwUiQMGFLAVAUFUTAQ8RgAktgAKiQYACIQqDU4Q90jlVA1dQ1EpORWr52nkikA

Why:

To avoid TS error or type-casting.

How:

The type error happens because TS tries to infer T from the variable breadcrumbs(BoundFunctions<T>) in the demo above. This is fixed by adding another generic variable K.

Checklist:

• [N/A ] Documentation added to the
  docs site
• Tests
• TypeScript definitions updated
• Ready to be merged
  

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[codecov]

Codecov Report

Merging #1077 (6e6515f) into main (b4ebc80) will not change coverage.
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[timdeschryver]

LGTM

[eps1lon]

No idea why this works. Added some more tests/comments to make sure this isn't reverted before checking git-blame.

[eps1lon]

@all-contributors add @robcaldecott for bug
@all-contributors add @Dennis273 for code

[allcontributors]

@eps1lon

I could not determine your intention.

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[eps1lon]

@all-contributors add @robcaldecott for bug

[eps1lon]

@all-contributors add @Dennis273 for code

[allcontributors]

@eps1lon

I've put up a pull request to add @robcaldecott! 🎉

[allcontributors]

@eps1lon

I've put up a pull request to add @Dennis273! 🎉

[eps1lon]

@all-contributors add @Dennis273 for code

[allcontributors]

@eps1lon

I've put up a pull request to add @Dennis273! 🎉

[github-actions]

🎉 This PR is included in version 8.11.2 🎉

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