wip

facebook · Sep 20, 2022 · 950ef9c · 950ef9c
1 parent 7a67594
commit 950ef9c
Show file tree

Hide file tree

Showing 3 changed files with 372 additions and 63 deletions.
diff --git a/packages/react-dom/src/__tests__/ReactDOMFloat-test.js b/packages/react-dom/src/__tests__/ReactDOMFloat-test.js
@@ -281,6 +281,55 @@ describe('ReactDOMFizzServer', () => {
         </html>,
       );
     });
+
+    it('inserts a preload resource when called in a layout effect', async () => {
+      function App() {
+        React.useLayoutEffect(() => {
+          console.log('calling preload inside useEffect');
+          ReactDOM.preload('foo', {as: 'style'});
+        }, []);
+        return 'foobar';
+      }
+      const root = ReactDOMClient.createRoot(container);
+      root.render(<App />);
+      expect(Scheduler).toFlushWithoutYielding();
+
+      console.log('document', document.documentElement.outerHTML);
+      expect(getVisibleChildren(document)).toEqual(
+        <html>
+          <head>
+            <link rel="preload" as="style" href="foo" />
+          </head>
+          <body>
+            <div id="container">foobar</div>
+          </body>
+        </html>,
+      );
+    });
+
+    fit('inserts a preload resource when called in a passive effect', async () => {
+      function App() {
+        React.useEffect(() => {
+          ReactDOM.preload('foo', {as: 'style'});
+        }, []);
+        return 'foobar';
+      }
+      const root = ReactDOMClient.createRoot(container);
+      root.render(<App />);
+      expect(Scheduler).toFlushWithoutYielding();
+
+      console.log('document', document.documentElement.outerHTML);
+      expect(getVisibleChildren(document)).toEqual(
+        <html>
+          <head>
+            <link rel="preload" as="style" href="foo" />
+          </head>
+          <body>
+            <div id="container">foobar</div>
+          </body>
+        </html>,
+      );
+    });
   });
 
   describe('style resources', () => {