Add React.useActionState

packages/react-debug-tools/src/ReactDebugHooks.js

@@ -103,6 +103,10 @@ function getPrimitiveStackCache(): Map<string, Array<any>> {
         // This type check is for Flow only.
         Dispatcher.useFormState((s: mixed, p: mixed) => s, null);
       }
+      if (typeof Dispatcher.useActionState === 'function') {
+        // This type check is for Flow only.
+        Dispatcher.useActionState((s: mixed, p: mixed) => s, null);
+      }
       if (typeof Dispatcher.use === 'function') {
         // This type check is for Flow only.
         Dispatcher.use(
@@ -586,6 +590,75 @@ function useFormState<S, P>(
   return [state, (payload: P) => {}, false];
 }
 
+function useActionState<S, P>(
+  action: (Awaited<S>, P) => S,
+  initialState: Awaited<S>,
+  permalink?: string,
+): [Awaited<S>, (P) => void, boolean] {
+  const hook = nextHook(); // FormState
+  nextHook(); // PendingState
+  nextHook(); // ActionQueue
+  const stackError = new Error();
+  let value;
+  let debugInfo = null;
+  let error = null;
+
+  if (hook !== null) {
+    const actionResult = hook.memoizedState;
+    if (
+      typeof actionResult === 'object' &&
+      actionResult !== null &&
+      // $FlowFixMe[method-unbinding]
+      typeof actionResult.then === 'function'
+    ) {
+      const thenable: Thenable<Awaited<S>> = (actionResult: any);
+      switch (thenable.status) {
+        case 'fulfilled': {
+          value = thenable.value;
+          debugInfo =
+            thenable._debugInfo === undefined ? null : thenable._debugInfo;
+          break;
+        }
+        case 'rejected': {
+          const rejectedError = thenable.reason;
+          error = rejectedError;
+          break;
+        }
+        default:
+          // If this was an uncached Promise we have to abandon this attempt
+          // but we can still emit anything up until this point.
+          error = SuspenseException;
+          debugInfo =
+            thenable._debugInfo === undefined ? null : thenable._debugInfo;
+          value = thenable;
+      }
+    } else {
+      value = (actionResult: any);
+    }
+  } else {
+    value = initialState;
+  }
+
+  hookLog.push({
+    displayName: null,
+    primitive: 'ActionState',
+    stackError: stackError,
+    value: value,
+    debugInfo: debugInfo,
+  });
+
+  if (error !== null) {
+    throw error;
+  }
+
+  // value being a Thenable is equivalent to error being not null
+  // i.e. we only reach this point with Awaited<S>
+  const state = ((value: any): Awaited<S>);
+
+  // TODO: support displaying pending value
+  return [state, (payload: P) => {}, false];
+}
+
 const Dispatcher: DispatcherType = {
   use,
   readContext,
@@ -608,6 +681,7 @@ const Dispatcher: DispatcherType = {
   useDeferredValue,
   useId,
   useFormState,
+  useActionState,
 };
 
 // create a proxy to throw a custom error

packages/react-dom/src/__tests__/ReactDOMFizzForm-test.js

@@ -24,6 +24,7 @@ let ReactDOMClient;
 let useFormStatus;
 let useOptimistic;
 let useFormState;
+let useActionState;
 
 describe('ReactDOMFizzForm', () => {
   beforeEach(() => {
@@ -34,6 +35,7 @@ describe('ReactDOMFizzForm', () => {
     useFormStatus = require('react-dom').useFormStatus;
     useFormState = require('react-dom').useFormState;
     useOptimistic = require('react').useOptimistic;
+    useActionState = require('react').useActionState;
     act = require('internal-test-utils').act;
     container = document.createElement('div');
     document.body.appendChild(container);
@@ -494,6 +496,28 @@ describe('ReactDOMFizzForm', () => {
     expect(container.textContent).toBe('0');
   });
 
+  // @gate enableFormActions
+  // @gate enableAsyncActions
+  it('useActionState returns initial state', async () => {
+    async function action(state) {
+      return state;
+    }
+
+    function App() {
+      const [state] = useActionState(action, 0);
+      return state;
+    }
+
+    const stream = await ReactDOMServer.renderToReadableStream(<App />);
+    await readIntoContainer(stream);
+    expect(container.textContent).toBe('0');
+
+    await act(async () => {
+      ReactDOMClient.hydrateRoot(container, <App />);
+    });
+    expect(container.textContent).toBe('0');
+  });
+
   // @gate enableFormActions
   it('can provide a custom action on the server for actions', async () => {
     const ref = React.createRef();

packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js

@@ -31,6 +31,7 @@ let useSyncExternalStore;
 let useSyncExternalStoreWithSelector;
 let use;
 let useFormState;
+let useActionState;
 let PropTypes;
 let textCache;
 let writable;
@@ -90,7 +91,7 @@ describe('ReactDOMFizzServer', () => {
       SuspenseList = React.unstable_SuspenseList;
     }
     useFormState = ReactDOM.useFormState;
-
+    useActionState = React.useActionState;
     PropTypes = require('prop-types');
 
     const InternalTestUtils = require('internal-test-utils');
@@ -6338,6 +6339,123 @@ describe('ReactDOMFizzServer', () => {
     expect(childRef.current).toBe(child);
   });
 
+  // @gate enableFormActions
+  // @gate enableAsyncActions
+  it('useActionState hydrates without a mismatch', async () => {
+    // This is testing an implementation detail: useActionState emits comment
+    // nodes into the SSR stream, so this checks that they are handled correctly
+    // during hydration.
+
+    async function action(state) {
+      return state;
+    }
+
+    const childRef = React.createRef(null);
+    function Form() {
+      const [state] = useActionState(action, 0);
+      const text = `Child: ${state}`;
+      return (
+        <div id="child" ref={childRef}>
+          {text}
+        </div>
+      );
+    }
+
+    function App() {
+      return (
+        <div>
+          <div>
+            <Form />
+          </div>
+          <span>Sibling</span>
+        </div>
+      );
+    }
+
+    await act(() => {
+      const {pipe} = renderToPipeableStream(<App />);
+      pipe(writable);
+    });
+    expect(getVisibleChildren(container)).toEqual(
+      <div>
+        <div>
+          <div id="child">Child: 0</div>
+        </div>
+        <span>Sibling</span>
+      </div>,
+    );
+    const child = document.getElementById('child');
+
+    // Confirm that it hydrates correctly
+    await clientAct(() => {
+      ReactDOMClient.hydrateRoot(container, <App />);
+    });
+    expect(childRef.current).toBe(child);
+  });
+
+  // @gate enableFormActions
+  // @gate enableAsyncActions
+  it("useActionState hydrates without a mismatch if there's a render phase update", async () => {
+    async function action(state) {
+      return state;
+    }
+
+    const childRef = React.createRef(null);
+    function Form() {
+      const [localState, setLocalState] = React.useState(0);
+      if (localState < 3) {
+        setLocalState(localState + 1);
+      }
+
+      // Because of the render phase update above, this component is evaluated
+      // multiple times (even during SSR), but it should only emit a single
+      // marker per useActionState instance.
+      const [formState] = useActionState(action, 0);
+      const text = `${readText('Child')}:${formState}:${localState}`;
+      return (
+        <div id="child" ref={childRef}>
+          {text}
+        </div>
+      );
+    }
+
+    function App() {
+      return (
+        <div>
+          <Suspense fallback="Loading...">
+            <Form />
+          </Suspense>
+          <span>Sibling</span>
+        </div>
+      );
+    }
+
+    await act(() => {
+      const {pipe} = renderToPipeableStream(<App />);
+      pipe(writable);
+    });
+    expect(getVisibleChildren(container)).toEqual(
+      <div>
+        Loading...<span>Sibling</span>
+      </div>,
+    );
+
+    await act(() => resolveText('Child'));
+    expect(getVisibleChildren(container)).toEqual(
+      <div>
+        <div id="child">Child:0:3</div>
+        <span>Sibling</span>
+      </div>,
+    );
+    const child = document.getElementById('child');
+
+    // Confirm that it hydrates correctly
+    await clientAct(() => {
+      ReactDOMClient.hydrateRoot(container, <App />);
+    });
+    expect(childRef.current).toBe(child);
+  });
+
   describe('useEffectEvent', () => {
     // @gate enableUseEffectEventHook
     it('can server render a component with useEffectEvent', async () => {