act shows up as deprecated when using react 18.3

[ambarvm]

• @testing-library/react version: 15.0.5
• Testing Framework and version: jest@29.2.1
• DOM Environment: jsdom@20.0.1

Relevant code or config:

import { act } from '@testing-library/react';
act(() => {});

Act is marked as deprecated.

The signature (callback: () => VoidOrUndefinedOnly): void of act is deprecated.

What you did:

Updated react to 18.3 in an existing project

What happened:

act imported from testing library is marked deprecated.

Reproduction:

https://stackblitz.com/edit/rtl-template-749zgo?file=src%2FApp.test.tsx

Problem description:

The js code correctly exports the new React.act which is not deprecated.

react-testing-library/src/act-compat.js

Line 5 in f6a1677

typeof React.act === 'function' ? React.act : DeprecatedReactTestUtils.act

But the types file always exports the type of deprecated act.

react-testing-library/types/index.d.ts

Line 10 in f6a1677

import {act as reactAct} from 'react-dom/test-utils'

Suggested solution:

Add another condition to the type definition to export React.act when it is present.

export const act: typeof reactAct extends undefined ? (typeof reactDomTestUtilsAct extends undefined
  ? (callback: () => void) => void
  : typeof reactDomTestUtilsAct) : typeof reactAct

I think we can also remove the case for act not being present since react peerDependency is ^18.

export const act: typeof reactAct extends undefined ? typeof reactDomTestUtilsAct : typeof reactAct

[MatanBobi]

Thanks @ambarvm, I've created #1319 to resolve this :)