Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[Fiber/Fizz] Support AsyncIterable as Children and AsyncGenerator Client Components #28868

Merged
merged 4 commits into from
Apr 22, 2024
Merged

[Fiber/Fizz] Support AsyncIterable as Children and AsyncGenerator Client Components #28868

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
73162be
Add Feature Flag
sebmarkbage Apr 17, 2024
9c37ac8
Warn for client Async Generator Function
sebmarkbage Apr 17, 2024
22ab188
Support Async Iterable Children in Fiber
sebmarkbage Apr 17, 2024
453d657
Support AsyncIterables in Fizz
sebmarkbage Apr 18, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
61 changes: 8 additions & 53 deletions packages/react-client/src/__tests__/ReactFlight-test.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2170,7 +2170,7 @@ describe('ReactFlight', () => {
);
});

// @gate enableFlightReadableStream
// @gate enableFlightReadableStream && enableAsyncIterableChildren
it('shares state when moving keyed Server Components that render async iterables', async () => {
function StatefulClient({name, initial}) {
const [state] = React.useState(initial);
Expand All @@ -2183,39 +2183,11 @@ describe('ReactFlight', () => {
yield <Stateful key="b" initial={'b' + initial} />;
}

function ListClient({children}) {
// TODO: Unwrap AsyncIterables natively in React. For now we do it in this wrapper.
const resolvedChildren = [];
// eslint-disable-next-line no-for-of-loops/no-for-of-loops
for (const fragment of children) {
// We should've wrapped each child in a keyed Fragment.
expect(fragment.type).toBe(React.Fragment);
const fragmentChildren = [];
const iterator = fragment.props.children[Symbol.asyncIterator]();
if (iterator === fragment.props.children) {
console.error(
'AyncIterators are not valid children of React. It must be a multi-shot AsyncIterable.',
);
}
for (let entry; !(entry = React.use(iterator.next())).done; ) {
fragmentChildren.push(entry.value);
}
resolvedChildren.push(
<React.Fragment key={fragment.key}>
{fragmentChildren}
</React.Fragment>,
);
}
return <div>{resolvedChildren}</div>;
}

const List = clientReference(ListClient);

const transport = ReactNoopFlightServer.render(
<List>
<div>
<ServerComponent key="A" initial={1} />
<ServerComponent key="B" initial={2} />
</List>,
</div>,
);

await act(async () => {
Expand All @@ -2234,10 +2206,10 @@ describe('ReactFlight', () => {
// We swap the Server Components and the state of each child inside each fragment should move.
// Really the Fragment itself moves.
const transport2 = ReactNoopFlightServer.render(
<List>
<div>
<ServerComponent key="B" initial={4} />
<ServerComponent key="A" initial={3} />
</List>,
</div>,
);

await act(async () => {
Expand Down Expand Up @@ -2336,7 +2308,7 @@ describe('ReactFlight', () => {
);
});

// @gate enableFlightReadableStream
// @gate enableFlightReadableStream && enableAsyncIterableChildren
it('preserves debug info for server-to-server pass through of async iterables', async () => {
let resolve;
const iteratorPromise = new Promise(r => (resolve = r));
Expand All @@ -2347,23 +2319,6 @@ describe('ReactFlight', () => {
resolve();
}

function ListClient({children: fragment}) {
// TODO: Unwrap AsyncIterables natively in React. For now we do it in this wrapper.
const resolvedChildren = [];
const iterator = fragment.props.children[Symbol.asyncIterator]();
if (iterator === fragment.props.children) {
console.error(
'AyncIterators are not valid children of React. It must be a multi-shot AsyncIterable.',
);
}
for (let entry; !(entry = React.use(iterator.next())).done; ) {
resolvedChildren.push(entry.value);
}
return <div>{resolvedChildren}</div>;
}

const List = clientReference(ListClient);

function Keyed({children}) {
// Keying this should generate a fragment.
return children;
Expand All @@ -2375,9 +2330,9 @@ describe('ReactFlight', () => {
ReactNoopFlightClient.read(transport),
).root;
return (
<List>
<div>
<Keyed key="keyed">{children}</Keyed>
</List>
</div>
);
}

Expand Down
68 changes: 66 additions & 2 deletions packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3346,7 +3346,7 @@ describe('ReactDOMFizzServer', () => {
]);
});

it('Supports iterable', async () => {
it('supports iterable', async () => {
const Immutable = require('immutable');

const mappedJSX = Immutable.fromJS([
Expand All @@ -3366,7 +3366,71 @@ describe('ReactDOMFizzServer', () => {
);
});

it('Supports bigint', async () => {
// @gate enableAsyncIterableChildren
it('supports async generator component', async () => {
async function* App() {
yield <span key="1">{await Promise.resolve('Hi')}</span>;
yield ' ';
yield <span key="2">{await Promise.resolve('World')}</span>;
}

await act(async () => {
const {pipe} = renderToPipeableStream(
<div>
<App />
</div>,
);
pipe(writable);
});

// Each act retries once which causes a new ping which schedules
// new work but only after the act has finished rendering.
await act(() => {});
await act(() => {});
await act(() => {});
await act(() => {});

expect(getVisibleChildren(container)).toEqual(
<div>
<span>Hi</span> <span>World</span>
</div>,
);
});

// @gate enableAsyncIterableChildren
it('supports async iterable children', async () => {
const iterable = {
async *[Symbol.asyncIterator]() {
yield <span key="1">{await Promise.resolve('Hi')}</span>;
yield ' ';
yield <span key="2">{await Promise.resolve('World')}</span>;
},
};

function App({children}) {
return <div>{children}</div>;
}

await act(() => {
const {pipe} = renderToPipeableStream(<App>{iterable}</App>);
pipe(writable);
});

// Each act retries once which causes a new ping which schedules
// new work but only after the act has finished rendering.
await act(() => {});
await act(() => {});
await act(() => {});
await act(() => {});

expect(getVisibleChildren(container)).toEqual(
<div>
<span>Hi</span> <span>World</span>
</div>,
);
});

it('supports bigint', async () => {
await act(async () => {
const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
<div>{10n}</div>,
Expand Down
118 changes: 112 additions & 6 deletions packages/react-reconciler/src/ReactChildFiber.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ import {
} from './ReactFiberFlags';
import {
getIteratorFn,
ASYNC_ITERATOR,
REACT_ELEMENT_TYPE,
REACT_FRAGMENT_TYPE,
REACT_PORTAL_TYPE,
Expand All @@ -41,7 +42,10 @@ import {
FunctionComponent,
} from './ReactWorkTags';
import isArray from 'shared/isArray';
import {enableRefAsProp} from 'shared/ReactFeatureFlags';
import {
enableRefAsProp,
enableAsyncIterableChildren,
} from 'shared/ReactFeatureFlags';

import {
createWorkInProgress,
Expand Down Expand Up @@ -576,7 +580,12 @@ function createChildReconciler(
}
}

if (isArray(newChild) || getIteratorFn(newChild)) {
if (
isArray(newChild) ||
getIteratorFn(newChild) ||
(enableAsyncIterableChildren &&
typeof newChild[ASYNC_ITERATOR] === 'function')
) {
const created = createFiberFromFragment(
newChild,
returnFiber.mode,
Expand Down Expand Up @@ -700,7 +709,12 @@ function createChildReconciler(
}
}

if (isArray(newChild) || getIteratorFn(newChild)) {
if (
isArray(newChild) ||
getIteratorFn(newChild) ||
(enableAsyncIterableChildren &&
typeof newChild[ASYNC_ITERATOR] === 'function')
) {
if (key !== null) {
return null;
}
Expand Down Expand Up @@ -822,7 +836,12 @@ function createChildReconciler(
);
}

if (isArray(newChild) || getIteratorFn(newChild)) {
if (
isArray(newChild) ||
getIteratorFn(newChild) ||
(enableAsyncIterableChildren &&
typeof newChild[ASYNC_ITERATOR] === 'function')
) {
const matchedFiber = existingChildren.get(newIdx) || null;
return updateFragment(
returnFiber,
Expand Down Expand Up @@ -1101,7 +1120,7 @@ function createChildReconciler(
return resultingFirstChild;
}

function reconcileChildrenIterator(
function reconcileChildrenIteratable(
returnFiber: Fiber,
currentFirstChild: Fiber | null,
newChildrenIterable: Iterable<mixed>,
Expand Down Expand Up @@ -1160,6 +1179,80 @@ function createChildReconciler(
}
}

return reconcileChildrenIterator(
returnFiber,
currentFirstChild,
newChildren,
lanes,
debugInfo,
);
}

function reconcileChildrenAsyncIteratable(
returnFiber: Fiber,
currentFirstChild: Fiber | null,
newChildrenIterable: AsyncIterable<mixed>,
lanes: Lanes,
debugInfo: ReactDebugInfo | null,
): Fiber | null {
const newChildren = newChildrenIterable[ASYNC_ITERATOR]();

if (__DEV__) {
if (newChildren === newChildrenIterable) {
// We don't support rendering AsyncGenerators as props because it's a mutation.
// We do support generators if they were created by a AsyncGeneratorFunction component
// as its direct child since we can recreate those by rerendering the component
// as needed.
const isGeneratorComponent =
returnFiber.tag === FunctionComponent &&
// $FlowFixMe[method-unbinding]
Object.prototype.toString.call(returnFiber.type) ===
'[object AsyncGeneratorFunction]' &&
// $FlowFixMe[method-unbinding]
Object.prototype.toString.call(newChildren) ===
'[object AsyncGenerator]';
if (!isGeneratorComponent) {
if (!didWarnAboutGenerators) {
console.error(
'Using AsyncIterators as children is unsupported and will likely yield ' +
'unexpected results because enumerating a generator mutates it. ' +
'You can use an AsyncIterable that can iterate multiple times over ' +
'the same items.',
);
}
didWarnAboutGenerators = true;
}
}
}

if (newChildren == null) {
throw new Error('An iterable object provided no iterator.');
}

// To save bytes, we reuse the logic by creating a synchronous Iterable and
// reusing that code path.
const iterator: Iterator<mixed> = ({
next(): IteratorResult<mixed, void> {
return unwrapThenable(newChildren.next());
},
}: any);

return reconcileChildrenIterator(
returnFiber,
currentFirstChild,
iterator,
lanes,
debugInfo,
);
}

function reconcileChildrenIterator(
returnFiber: Fiber,
currentFirstChild: Fiber | null,
newChildren: ?Iterator<mixed>,
lanes: Lanes,
debugInfo: ReactDebugInfo | null,
): Fiber | null {
if (newChildren == null) {
throw new Error('An iterable object provided no iterator.');
}
Expand Down Expand Up @@ -1552,7 +1645,20 @@ function createChildReconciler(
}

if (getIteratorFn(newChild)) {
return reconcileChildrenIterator(
return reconcileChildrenIteratable(
returnFiber,
currentFirstChild,
newChild,
lanes,
mergeDebugInfo(debugInfo, newChild._debugInfo),
);
}

if (
enableAsyncIterableChildren &&
typeof newChild[ASYNC_ITERATOR] === 'function'
) {
return reconcileChildrenAsyncIteratable(
returnFiber,
currentFirstChild,
newChild,
Expand Down
5 changes: 4 additions & 1 deletion packages/react-reconciler/src/ReactFiberHooks.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -414,7 +414,10 @@ function warnIfAsyncClientComponent(Component: Function) {
// bulletproof but together they cover the most common cases.
const isAsyncFunction =
// $FlowIgnore[method-unbinding]
Object.prototype.toString.call(Component) === '[object AsyncFunction]';
Object.prototype.toString.call(Component) === '[object AsyncFunction]' ||
// $FlowIgnore[method-unbinding]
Object.prototype.toString.call(Component) ===
'[object AsyncGeneratorFunction]';
if (isAsyncFunction) {
// Encountered an async Client Component. This is not yet supported.
const componentName = getComponentNameFromFiber(currentlyRenderingFiber);
Expand Down
Loading