test

packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js

@@ -13,9 +13,14 @@ let ReactNoop;
 let Scheduler;
 let act;
 
+let getCacheForType;
 let useState;
+let Suspense;
 let startTransition;
 
+let caches;
+let seededCache;
+
 describe('ReactInteractionTracing', () => {
   beforeEach(() => {
     jest.resetModules();
@@ -28,13 +33,121 @@ describe('ReactInteractionTracing', () => {
 
     useState = React.useState;
     startTransition = React.startTransition;
+    Suspense = React.Suspense;
+
+    getCacheForType = React.unstable_getCacheForType;
+
+    caches = [];
+    seededCache = null;
   });
 
+  function createTextCache() {
+    if (seededCache !== null) {
+      const cache = seededCache;
+      seededCache = null;
+      return cache;
+    }
+
+    const data = new Map();
+    const cache = {
+      data,
+      resolve(text) {
+        const record = data.get(text);
+
+        if (record === undefined) {
+          const newRecord = {
+            status: 'resolved',
+            value: text,
+          };
+          data.set(text, newRecord);
+        } else if (record.status === 'pending') {
+          const thenable = record.value;
+          record.status = 'resolved';
+          record.value = text;
+          thenable.pings.forEach(t => t());
+        }
+      },
+      reject(text, error) {
+        const record = data.get(text);
+        if (record === undefined) {
+          const newRecord = {
+            status: 'rejected',
+            value: error,
+          };
+          data.set(text, newRecord);
+        } else if (record.status === 'pending') {
+          const thenable = record.value;
+          record.status = 'rejected';
+          record.value = error;
+          thenable.pings.forEach(t => t());
+        }
+      },
+    };
+    caches.push(cache);
+    return cache;
+  }
+
+  function readText(text) {
+    const textCache = getCacheForType(createTextCache);
+    const record = textCache.data.get(text);
+    if (record !== undefined) {
+      switch (record.status) {
+        case 'pending':
+          Scheduler.unstable_yieldValue(`Suspend [${text}]`);
+          throw record.value;
+        case 'rejected':
+          Scheduler.unstable_yieldValue(`Error [${text}]`);
+          throw record.value;
+        case 'resolved':
+          return record.value;
+      }
+    } else {
+      Scheduler.unstable_yieldValue(`Suspend [${text}]`);
+
+      const thenable = {
+        pings: [],
+        then(resolve) {
+          if (newRecord.status === 'pending') {
+            thenable.pings.push(resolve);
+          } else {
+            Promise.resolve().then(() => resolve(newRecord.value));
+          }
+        },
+      };
+
+      const newRecord = {
+        status: 'pending',
+        value: thenable,
+      };
+      textCache.data.set(text, newRecord);
+
+      throw thenable;
+    }
+  }
+
+  function AsyncText({text}) {
+    const fullText = readText(text);
+    Scheduler.unstable_yieldValue(fullText);
+    return fullText;
+  }
+
   function Text({text}) {
     Scheduler.unstable_yieldValue(text);
     return text;
   }
 
+  function resolveMostRecentTextCache(text) {
+    if (caches.length === 0) {
+      throw Error('Cache does not exist');
+    } else {
+      // Resolve the most recently created cache. An older cache can by
+      // resolved with `caches[index].resolve(text)`.
+      caches[caches.length - 1].resolve(text);
+    }
+  }
+
+  const resolveText = resolveMostRecentTextCache;
+
   function advanceTimers(ms) {
     // Note: This advances Jest's virtual time but not React's. Use
     // ReactNoop.expire for that.
@@ -98,4 +211,72 @@ describe('ReactInteractionTracing', () => {
       });
     });
   });
+
+  // @gate enableTransitionTracing
+  it('should correctly trace interactions for async roots', async () => {
+    const transitionCallbacks = {
+      onTransitionStart: (name, startTime) => {
+        Scheduler.unstable_yieldValue(
+          `onTransitionStart(${name}, ${startTime})`,
+        );
+      },
+      onTransitionComplete: (name, startTime, endTime) => {
+        Scheduler.unstable_yieldValue(
+          `onTransitionComplete(${name}, ${startTime}, ${endTime})`,
+        );
+      },
+    };
+    let navigateToPageTwo;
+    function App() {
+      const [navigate, setNavigate] = useState(false);
+      navigateToPageTwo = () => {
+        setNavigate(true);
+      };
+
+      return (
+        <div>
+          {navigate ? (
+            <Suspense
+              fallback={<Text text="Loading..." />}
+              name="suspense page">
+              <AsyncText text="Page Two" />
+            </Suspense>
+          ) : (
+            <Text text="Page One" />
+          )}
+        </div>
+      );
+    }
+
+    const root = ReactNoop.createRoot({transitionCallbacks});
+    await act(async () => {
+      root.render(<App />);
+      ReactNoop.expire(1000);
+      await advanceTimers(1000);
+
+      expect(Scheduler).toFlushAndYield(['Page One']);
+    });
+
+    await act(async () => {
+      startTransition(() => navigateToPageTwo(), {name: 'page transition'});
+
+      ReactNoop.expire(1000);
+      await advanceTimers(1000);
+
+      expect(Scheduler).toFlushAndYield([
+        'Suspend [Page Two]',
+        'Loading...',
+        'onTransitionStart(page transition, 1000)',
+      ]);
+
+      ReactNoop.expire(1000);
+      await advanceTimers(1000);
+      await resolveText('Page Two');
+
+      expect(Scheduler).toFlushAndYield([
+        'Page Two',
+        'onTransitionComplete(page transition, 1000, 3000)',
+      ]);
+    });
+  });
 });