[v14]: chore: use async act by default

mdjastrzebski · mdjastrzebski · commit fdc80b4b7e43 · 2026-01-05T11:49:40.000+01:00
diff --git a/src/act.ts b/src/act.ts
@@ -66,7 +66,10 @@ function withGlobalActEnvironment(actImplementation: ReactAct) {
   };
 }
 
-const act = withGlobalActEnvironment(reactAct) as ReactAct;
+export const unsafe_act = withGlobalActEnvironment(reactAct) as ReactAct;
+
+export function act<T>(callback: () => T | Promise<T>): Promise<T> {
+  return unsafe_act(async () => await callback());
+}
 
-export default act;
 export { getIsReactActEnvironment, setIsReactActEnvironment as setReactActEnvironment };
diff --git a/src/fire-event.ts b/src/fire-event.ts
@@ -7,7 +7,7 @@ import type {
 } from 'react-native';
 import type { Fiber, HostElement } from 'universal-test-renderer';
 
-import act from './act';
+import { act, unsafe_act } from './act';
 import type { EventHandler } from './event-handler';
 import { getEventHandlerFromProps } from './event-handler';
 import { isElementMounted, isHostElement } from './helpers/component-tree';
@@ -139,8 +139,7 @@ async function fireEvent(element: HostElement, eventName: EventName, ...data: un
   }
 
   let returnValue;
-  // eslint-disable-next-line require-await
-  await act(async () => {
+  await act(() => {
     returnValue = handler(...data);
   });
 
@@ -170,7 +169,7 @@ function unsafe_fireEventSync(element: HostElement, eventName: EventName, ...dat
   }
 
   let returnValue;
-  void act(() => {
+  void unsafe_act(() => {
     returnValue = handler(...data);
   });
 
diff --git a/src/pure.ts b/src/pure.ts
@@ -1,4 +1,4 @@
-export { default as act } from './act';
+export { act, unsafe_act } from './act';
 export { cleanup } from './cleanup';
 export { fireEvent, unsafe_fireEventSync } from './fire-event';
 export { render } from './render';
diff --git a/src/render-act.ts b/src/render-act.ts
diff --git a/src/render.tsx b/src/render.tsx
@@ -1,13 +1,18 @@
 import * as React from 'react';
-import type { HostElement, JsonElement, Root, RootOptions } from 'universal-test-renderer';
-
-import act from './act';
+import {
+  createRoot,
+  type HostElement,
+  type JsonElement,
+  type Root,
+  type RootOptions,
+} from 'universal-test-renderer';
+
+import { act } from './act';
 import { addToCleanupQueue } from './cleanup';
 import { getConfig } from './config';
 import type { DebugOptions } from './helpers/debug';
 import { debug } from './helpers/debug';
 import { HOST_TEXT_NAMES } from './helpers/host-component-names';
-import { renderWithAsyncAct } from './render-act';
 import { setRenderResult } from './screen';
 import { getQueriesForElement } from './within';
 
@@ -28,7 +33,7 @@ export type RenderResult = Awaited<ReturnType<typeof render>>;
  * Renders test component deeply using React Test Renderer and exposes helpers
  * to assert on the output.
  */
-export async function render<T>(component: React.ReactElement<T>, options: RenderOptions = {}) {
+export async function render<T>(element: React.ReactElement<T>, options: RenderOptions = {}) {
   const { wrapper: Wrapper, createNodeMock } = options || {};
 
   const rendererOptions: RootOptions = {
@@ -37,26 +42,22 @@ export async function render<T>(component: React.ReactElement<T>, options: Rende
   };
 
   const wrap = (element: React.ReactElement) => (Wrapper ? <Wrapper>{element}</Wrapper> : element);
-  const renderer = await renderWithAsyncAct(wrap(component), rendererOptions);
-  return buildRenderResult(renderer, wrap);
-}
+  const renderer = createRoot(rendererOptions);
+
+  await act(() => {
+    renderer.render(wrap(element));
+  });
 
-function buildRenderResult(
-  renderer: Root,
-  wrap: (element: React.ReactElement) => React.JSX.Element,
-) {
   const container = renderer.container;
 
   const rerender = async (component: React.ReactElement) => {
-    // eslint-disable-next-line require-await
-    await act(async () => {
+    await act(() => {
       renderer.render(wrap(component));
     });
   };
 
   const unmount = async () => {
-    // eslint-disable-next-line require-await
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
   };
diff --git a/src/unsafe-render-sync.tsx b/src/unsafe-render-sync.tsx
@@ -1,13 +1,18 @@
 import * as React from 'react';
-import type { HostElement, JsonElement, Root, RootOptions } from 'universal-test-renderer';
-
-import act from './act';
+import {
+  createRoot,
+  type HostElement,
+  type JsonElement,
+  type Root,
+  type RootOptions,
+} from 'universal-test-renderer';
+
+import { act, unsafe_act } from './act';
 import { addToCleanupQueue } from './cleanup';
 import { getConfig } from './config';
 import type { DebugOptions } from './helpers/debug';
 import { debug } from './helpers/debug';
 import { HOST_TEXT_NAMES } from './helpers/host-component-names';
-import { renderWithAct } from './render-act';
 import { setRenderResult } from './screen';
 import { getQueriesForElement } from './within';
 
@@ -45,36 +50,33 @@ export function renderInternal<T>(component: React.ReactElement<T>, options?: Re
   };
 
   const wrap = (element: React.ReactElement) => (Wrapper ? <Wrapper>{element}</Wrapper> : element);
-  const renderer = renderWithAct(wrap(component), rendererOptions);
-  return buildRenderResult(renderer, wrap);
-}
 
-function buildRenderResult(
-  renderer: Root,
-  wrap: (element: React.ReactElement) => React.JSX.Element,
-) {
+  const renderer = createRoot(rendererOptions);
+
+  unsafe_act(() => {
+    renderer.render(wrap(component));
+  });
+
   const rerender = (component: React.ReactElement) => {
-    void act(() => {
+    unsafe_act(() => {
       renderer.render(wrap(component));
     });
   };
 
   const rerenderAsync = async (component: React.ReactElement) => {
-    // eslint-disable-next-line require-await
-    await act(async () => {
+    await act(() => {
       renderer.render(wrap(component));
     });
   };
 
   const unmount = () => {
-    void act(() => {
+    unsafe_act(() => {
       renderer.unmount();
     });
   };
 
   const unmountAsync = async () => {
-    // eslint-disable-next-line require-await
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
   };
diff --git a/src/user-event/press/press.ts b/src/user-event/press/press.ts
@@ -1,6 +1,6 @@
 import type { HostElement } from 'universal-test-renderer';
 
-import act from '../../act';
+import { act } from '../../act';
 import { getEventHandlerFromProps } from '../../event-handler';
 import { isHostElement } from '../../helpers/component-tree';
 import { ErrorWithStack } from '../../helpers/errors';
diff --git a/src/user-event/utils/dispatch-event.ts b/src/user-event/utils/dispatch-event.ts
@@ -1,6 +1,6 @@
 import type { HostElement } from 'universal-test-renderer';
 
-import act from '../../act';
+import { act } from '../../act';
 import { getEventHandlerFromProps } from '../../event-handler';
 import { isElementMounted } from '../../helpers/component-tree';
 
@@ -21,8 +21,7 @@ export async function dispatchEvent(element: HostElement, eventName: string, ...
     return;
   }
 
-  // eslint-disable-next-line require-await
-  await act(async () => {
+  await act(() => {
     handler(...event);
   });
 }
diff --git a/src/wait-for.ts b/src/wait-for.ts
@@ -1,5 +1,5 @@
 /* globals jest */
-import act from './act';
+import { act } from './act';
 import { getConfig } from './config';
 import { flushMicroTasks } from './flush-micro-tasks';
 import { copyStackTrace, ErrorWithStack } from './helpers/errors';
@@ -70,7 +70,7 @@ function waitForInternal<T>(
         // third party code that's setting up recursive timers so rapidly that
         // the user's timer's don't get a chance to resolve. So we'll advance
         // by an interval instead. (We have a test for this case).
-        await act(async () => await jest.advanceTimersByTime(interval));
+        await act(() => jest.advanceTimersByTime(interval));
 
         // It's really important that checkExpectation is run *before* we flush
         // in-flight promises. To be honest, I'm not sure why, and I can't quite
diff --git a/website/docs/14.x/docs/advanced/understanding-act.mdx b/website/docs/14.x/docs/advanced/understanding-act.mdx
@@ -61,9 +61,9 @@ test('render without act', () => {
 When testing without `act` call wrapping rendering call, we see that the assertion runs just after the rendering but before `useEffect`hooks effects are applied. Which is not what we expected in our tests.
 
 ```jsx
-test('render with act', () => {
+test('render with act', async () => {
   let renderer: ReactTestRenderer;
-  act(() => {
+  await act(async () => {
     renderer = TestRenderer.create(<TestComponent />);
   });
 
@@ -73,6 +73,8 @@ test('render with act', () => {
 });
 ```
 
+**Note**: In v14, `act` is now async by default and always returns a Promise. Even if your callback is synchronous, you should use `await act(async () => ...)`.
+
 When wrapping rendering call with `act` we see that the changes caused by `useEffect` hook have been applied as we would expect.
 
 ### When to use act
@@ -95,7 +97,7 @@ Note that `act` calls can be safely nested and internally form a stack of calls.
 
 As of React version of 18.1.0, the `act` implementation is defined in the [ReactAct.js source file](https://github.com/facebook/react/blob/main/packages/react/src/ReactAct.js) inside React repository. This implementation has been fairly stable since React 17.0.
 
-RNTL exports `act` for convenience of the users as defined in the [act.ts source file](https://github.com/callstack/react-native-testing-library/blob/main/src/act.ts). That file refers to [ReactTestRenderer.js source](https://github.com/facebook/react/blob/ce13860281f833de8a3296b7a3dad9caced102e9/packages/react-test-renderer/src/ReactTestRenderer.js#L52) file from React Test Renderer package, which finally leads to React act implementation in ReactAct.js (already mentioned above).
+RNTL exports `act` for convenience of the users as defined in the [act.ts source file](https://github.com/callstack/react-native-testing-library/blob/main/src/act.ts). In v14, `act` is now async by default and always returns a Promise, making it compatible with React 19, React Suspense, and `React.use()`. The underlying implementation still uses React's `act` function, but wraps it to ensure consistent async behavior.
 
 ## Asynchronous `act`
 
@@ -149,17 +151,19 @@ Note that this is not yet the infamous async act warning. It only asks us to wra
 First solution is to use Jest's fake timers inside out tests:
 
 ```jsx
-test('render with fake timers', () => {
+test('render with fake timers', async () => {
   jest.useFakeTimers();
   render(<TestAsyncComponent />);
 
-  act(() => {
+  await act(async () => {
     jest.runAllTimers();
   });
   expect(screen.getByText('Count 1')).toBeOnTheScreen();
 });
 ```
 
+**Note**: In v14, `act` is now async by default, so you should await it even when using fake timers.
+
 That way we can wrap `jest.runAllTimers()` call which triggers the `setTimeout` updates inside an `act` call, hence resolving the act warning. Note that this whole code is synchronous thanks to usage of Jest fake timers.
 
 ### Solution with real timers
diff --git a/website/docs/14.x/docs/api/misc/other.mdx b/website/docs/14.x/docs/api/misc/other.mdx
@@ -29,10 +29,51 @@ Use cases for scoped queries include:
 
 ## `act`
 
-Useful function to help testing components that use hooks API. By default any `render`, `update`, `fireEvent`, and `waitFor` calls are wrapped by this function, so there is no need to wrap it manually. This method is provided by [Universal Test Renderer](https://github.com/callstack/universal-test-renderer) and re-exported for convenience.
+```ts
+function act<T>(callback: () => T | Promise<T>): Promise<T>;
+```
+
+Useful function to help testing components that use hooks API. By default any `render`, `update`, `fireEvent`, and `waitFor` calls are wrapped by this function, so there is no need to wrap it manually.
+
+**In v14, `act` is now async by default and always returns a Promise**, making it compatible with React 19, React Suspense, and `React.use()`. This ensures all pending React updates are executed before the Promise resolves.
+
+```ts
+import { act } from '@testing-library/react-native';
+
+it('should update state', async () => {
+  await act(async () => {
+    setState('new value');
+  });
+  expect(state).toBe('new value');
+});
+```
+
+**Note**: Even if your callback is synchronous, you should still use `await act(async () => ...)` as `act` now always returns a Promise.
 
 Consult our [Understanding Act function](docs/advanced/understanding-act.md) document for more understanding of its intricacies.
 
+## `unsafe_act`
+
+```ts
+function unsafe_act<T>(callback: () => T | Promise<T>): T | Thenable<T>;
+```
+
+**⚠️ Deprecated**: This function is provided for migration purposes only. Use async `act` instead.
+
+The synchronous version of `act` that maintains the same behavior as v13. It returns immediately for sync callbacks or a thenable for async callbacks. This is not recommended for new code as it doesn't work well with React 19's async features.
+
+```ts
+// Deprecated - use act instead
+import { unsafe_act } from '@testing-library/react-native';
+
+it('should update state', () => {
+  unsafe_act(() => {
+    setState('new value');
+  });
+  expect(state).toBe('new value');
+});
+```
+
 ## `cleanup`
 
 ```ts
diff --git a/website/docs/14.x/docs/migration/v14.mdx b/website/docs/14.x/docs/migration/v14.mdx

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-export { default as act } from './act';`
	`1`	`+export { act, unsafe_act } from './act';`
`2`	`2`	`export { cleanup } from './cleanup';`
`3`	`3`	`export { fireEvent, unsafe_fireEventSync } from './fire-event';`
`4`	`4`	`export { render } from './render';`
Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,6 @@`
`1`	`1`	`import type { HostElement } from 'universal-test-renderer';`
`2`	`2`
`3`		`-import act from '../../act';`
	`3`	`+import { act } from '../../act';`
`4`	`4`	`import { getEventHandlerFromProps } from '../../event-handler';`
`5`	`5`	`import { isElementMounted } from '../../helpers/component-tree';`
`6`	`6`
`@@ -21,8 +21,7 @@ export async function dispatchEvent(element: HostElement, eventName: string, ...`
`21`	`21`	`return;`
`22`	`22`	`}`
`23`	`23`
`24`		`- // eslint-disable-next-line require-await`
`25`		`- await act(async () => {`
	`24`	`+ await act(() => {`
`26`	`25`	`handler(...event);`
`27`	`26`	`});`
`28`	`27`	`}`