Import maps need to be emitted before any scripts or preloads so the browser can properly locate these resources. This change makes React aware of the concept of import maps and emits them before scripts and modules and their preloads.

gnoff · gnoff · commit 71bd635ba6e7 · 2023-08-22T14:35:43.000-07:00
diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
@@ -139,6 +139,7 @@ export type RenderState = {
   // Hoistable chunks
   charsetChunks: Array<Chunk | PrecomputedChunk>,
   preconnectChunks: Array<Chunk | PrecomputedChunk>,
+  importMapChunks: Array<Chunk | PrecomputedChunk>,
   preloadChunks: Array<Chunk | PrecomputedChunk>,
   hoistableChunks: Array<Chunk | PrecomputedChunk>,
 
@@ -205,7 +206,7 @@ const scriptCrossOrigin = stringToPrecomputedChunk('" crossorigin="');
 const endAsyncScript = stringToPrecomputedChunk('" async=""></script>');
 
 /**
- * This escaping function is designed to work with bootstrapScriptContent only.
+ * This escaping function is designed to work with bootstrapScriptContent and importMap only.
  * because we know we are escaping the entire script. We can avoid for instance
  * escaping html comment string sequences that are valid javascript as well because
  * if there are no sebsequent <script sequences the html parser will never enter
@@ -214,7 +215,7 @@ const endAsyncScript = stringToPrecomputedChunk('" async=""></script>');
  * While untrusted script content should be made safe before using this api it will
  * ensure that the script cannot be early terminated or never terminated state
  */
-function escapeBootstrapScriptContent(scriptText: string) {
+function escapeBootstrapAndImportMapScriptContent(scriptText: string) {
   if (__DEV__) {
     checkHtmlStringCoercion(scriptText);
   }
@@ -237,12 +238,19 @@ export type ExternalRuntimeScript = {
   src: string,
   chunks: Array<Chunk | PrecomputedChunk>,
 };
+
+const importMapScriptStart = stringToPrecomputedChunk(
+  '<script type="importmap">',
+);
+const importMapScriptEnd = stringToPrecomputedChunk('</script>');
+
 // Allows us to keep track of what we've already written so we can refer back to it.
 // if passed externalRuntimeConfig and the enableFizzExternalRuntime feature flag
 // is set, the server will send instructions via data attributes (instead of inline scripts)
 export function createRenderState(
   resumableState: ResumableState,
   nonce: string | void,
+  importMap: {[string]: string} | void,
 ): RenderState {
   const inlineScriptWithNonce =
     nonce === undefined
@@ -251,6 +259,17 @@ export function createRenderState(
           '<script nonce="' + escapeTextForBrowser(nonce) + '">',
         );
   const idPrefix = resumableState.idPrefix;
+  const importMapChunks: Array<Chunk | PrecomputedChunk> = [];
+  if (importMap !== undefined) {
+    const map = importMap;
+    importMapChunks.push(importMapScriptStart);
+    importMapChunks.push(
+      stringToChunk(
+        escapeBootstrapAndImportMapScriptContent(JSON.stringify(map)),
+      ),
+    );
+    importMapChunks.push(importMapScriptEnd);
+  }
   return {
     placeholderPrefix: stringToPrecomputedChunk(idPrefix + 'P:'),
     segmentPrefix: stringToPrecomputedChunk(idPrefix + 'S:'),
@@ -260,6 +279,7 @@ export function createRenderState(
     headChunks: null,
     charsetChunks: [],
     preconnectChunks: [],
+    importMapChunks,
     preloadChunks: [],
     hoistableChunks: [],
     nonce,
@@ -290,7 +310,9 @@ export function createResumableState(
           );
     bootstrapChunks.push(
       inlineScriptWithNonce,
-      stringToChunk(escapeBootstrapScriptContent(bootstrapScriptContent)),
+      stringToChunk(
+        escapeBootstrapAndImportMapScriptContent(bootstrapScriptContent),
+      ),
       endInlineScript,
     );
   }
@@ -4342,6 +4364,12 @@ export function writePreamble(
   // Flush unblocked stylesheets by precedence
   resumableState.precedences.forEach(flushAllStylesInPreamble, destination);
 
+  const importMapChunks = renderState.importMapChunks;
+  for (i = 0; i < importMapChunks.length; i++) {
+    writeChunk(destination, importMapChunks[i]);
+  }
+  importMapChunks.length = 0;
+
   resumableState.bootstrapScripts.forEach(flushResourceInPreamble, destination);
 
   resumableState.scripts.forEach(flushResourceInPreamble, destination);
@@ -4415,6 +4443,11 @@ export function writeHoistables(
   // but we want to kick off preloading as soon as possible
   resumableState.precedences.forEach(preloadLateStyles, destination);
 
+  // We only hoist importmaps that are configured through createResponse and that will
+  // always flush in the preamble. Generally we don't expect people to render them as
+  // tags when using React but if you do they are going to be treated like regular inline
+  // scripts and flush after other hoistables which is problematic
+
   // bootstrap scripts should flush above script priority but these can only flush in the preamble
   // so we elide the code here for performance
 
diff --git a/packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js b/packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js
@@ -41,6 +41,7 @@ export type RenderState = {
   headChunks: null | Array<Chunk | PrecomputedChunk>,
   charsetChunks: Array<Chunk | PrecomputedChunk>,
   preconnectChunks: Array<Chunk | PrecomputedChunk>,
+  importMapChunks: Array<Chunk | PrecomputedChunk>,
   preloadChunks: Array<Chunk | PrecomputedChunk>,
   hoistableChunks: Array<Chunk | PrecomputedChunk>,
   boundaryResources: ?BoundaryResources,
@@ -65,6 +66,7 @@ export function createRenderState(
     headChunks: renderState.headChunks,
     charsetChunks: renderState.charsetChunks,
     preconnectChunks: renderState.preconnectChunks,
+    importMapChunks: renderState.importMapChunks,
     preloadChunks: renderState.preloadChunks,
     hoistableChunks: renderState.hoistableChunks,
     boundaryResources: renderState.boundaryResources,
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -3623,6 +3623,33 @@ describe('ReactDOMFizzServer', () => {
     await waitForAll([]);
   });
 
+  it('takes an importMap option which emits an "importmap" script in the head', async () => {
+    const importMap = {
+      foo: './path/to/foo.js',
+    };
+    await act(() => {
+      renderToPipeableStream(
+        <html>
+          <head>
+            <script async={true} src="foo" />
+          </head>
+          <body>
+            <div>hello world</div>
+          </body>
+        </html>,
+        {
+          importMap,
+        },
+      ).pipe(writable);
+    });
+
+    expect(document.head.innerHTML).toBe(
+      '<script type="importmap">' +
+        JSON.stringify(importMap) +
+        '</script><script async="" src="foo"></script>',
+    );
+  });
+
   describe('error escaping', () => {
     it('escapes error hash, message, and component stack values in directly flushed errors (html escaping)', async () => {
       window.__outlet = {};
@@ -3949,7 +3976,7 @@ describe('ReactDOMFizzServer', () => {
     ]);
   });
 
-  describe('bootstrapScriptContent escaping', () => {
+  describe('bootstrapScriptContent and importMap escaping', () => {
     it('the "S" in "</?[Ss]cript" strings are replaced with unicode escaped lowercase s or S depending on case, preserving case sensitivity of nearby characters', async () => {
       window.__test_outlet = '';
       const stringWithScriptsInIt =
@@ -4005,6 +4032,24 @@ describe('ReactDOMFizzServer', () => {
       });
       expect(window.__test_outlet).toBe(1);
     });
+
+    it('escapes </[sS]cirpt> in importMaps', async () => {
+      window.__test_outlet_key = '';
+      window.__test_outlet_value = '';
+      const jsonWithScriptsInIt = {
+        "keypos</script><script>window.__test_outlet_key = 'pwned'</script><script>":
+          'value',
+        key: "valuepos</script><script>window.__test_outlet_value = 'pwned'</script><script>",
+      };
+      await act(() => {
+        const {pipe} = renderToPipeableStream(<div />, {
+          importMap: jsonWithScriptsInIt,
+        });
+        pipe(writable);
+      });
+      expect(window.__test_outlet_key).toBe('');
+      expect(window.__test_outlet_value).toBe('');
+    });
   });
 
   // @gate enableFizzExternalRuntime
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzStatic-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzStatic-test.js
@@ -84,6 +84,10 @@ describe('ReactDOMFizzStatic', () => {
       if (node.nodeName === 'SCRIPT') {
         const script = document.createElement('script');
         script.textContent = node.textContent;
+        for (let i = 0; i < node.attributes.length; i++) {
+          const attribute = node.attributes[i];
+          script.setAttribute(attribute.name, attribute.value);
+        }
         fakeBody.removeChild(node);
         container.appendChild(script);
       } else {
@@ -98,7 +102,7 @@ describe('ReactDOMFizzStatic', () => {
     while (node) {
       if (node.nodeType === 1) {
         if (
-          node.tagName !== 'SCRIPT' &&
+          (node.tagName !== 'SCRIPT' || node.hasAttribute('type')) &&
           node.tagName !== 'TEMPLATE' &&
           node.tagName !== 'template' &&
           !node.hasAttribute('hidden') &&
@@ -237,4 +241,24 @@ describe('ReactDOMFizzStatic', () => {
 
     expect(getVisibleChildren(container)).toEqual(<div>Hello</div>);
   });
+
+  it('should support importMap option', async () => {
+    const importMap = {
+      foo: 'path/to/foo.js',
+    };
+    const result = await ReactDOMFizzStatic.prerenderToNodeStream(
+      <html>
+        <body>hello world</body>
+      </html>,
+      {importMap},
+    );
+
+    await act(async () => {
+      result.prelude.pipe(writable);
+    });
+    expect(getVisibleChildren(container)).toEqual([
+      <script type="importmap">{JSON.stringify(importMap)}</script>,
+      'hello world',
+    ]);
+  });
 });
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js b/packages/react-dom/src/server/ReactDOMFizzServerBrowser.js
@@ -38,6 +38,7 @@ type Options = {
   onError?: (error: mixed) => ?string,
   onPostpone?: (reason: string) => void,
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
+  importMap?: {[string]: string},
 };
 
 type ResumeOptions = {
@@ -101,7 +102,11 @@ function renderToReadableStream(
     const request = createRequest(
       children,
       resumableState,
-      createRenderState(resumableState, options ? options.nonce : undefined),
+      createRenderState(
+        resumableState,
+        options ? options.nonce : undefined,
+        options ? options.importMap : undefined,
+      ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
       options ? options.onError : undefined,
@@ -171,6 +176,7 @@ function resume(
       createRenderState(
         postponedState.resumableState,
         options ? options.nonce : undefined,
+        undefined, // importMap
       ),
       postponedState.rootFormatContext,
       postponedState.progressiveChunkSize,
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerBun.js b/packages/react-dom/src/server/ReactDOMFizzServerBun.js
@@ -37,6 +37,7 @@ type Options = {
   onError?: (error: mixed) => ?string,
   onPostpone?: (reason: string) => void,
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
+  importMap?: {[string]: string},
 };
 
 // TODO: Move to sub-classing ReadableStream.
@@ -93,7 +94,11 @@ function renderToReadableStream(
     const request = createRequest(
       children,
       resumableState,
-      createRenderState(resumableState, options ? options.nonce : undefined),
+      createRenderState(
+        resumableState,
+        options ? options.nonce : undefined,
+        options ? options.importMap : undefined,
+      ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
       options ? options.onError : undefined,
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerEdge.js b/packages/react-dom/src/server/ReactDOMFizzServerEdge.js
@@ -38,6 +38,7 @@ type Options = {
   onError?: (error: mixed) => ?string,
   onPostpone?: (reason: string) => void,
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
+  importMap?: {[string]: string},
 };
 
 type ResumeOptions = {
@@ -101,7 +102,11 @@ function renderToReadableStream(
     const request = createRequest(
       children,
       resumableState,
-      createRenderState(resumableState, options ? options.nonce : undefined),
+      createRenderState(
+        resumableState,
+        options ? options.nonce : undefined,
+        options ? options.importMap : undefined,
+      ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
       options ? options.onError : undefined,
@@ -171,6 +176,7 @@ function resume(
       createRenderState(
         postponedState.resumableState,
         options ? options.nonce : undefined,
+        undefined, // importMap
       ),
       postponedState.rootFormatContext,
       postponedState.progressiveChunkSize,
diff --git a/packages/react-dom/src/server/ReactDOMFizzServerNode.js b/packages/react-dom/src/server/ReactDOMFizzServerNode.js
@@ -51,6 +51,7 @@ type Options = {
   onError?: (error: mixed) => ?string,
   onPostpone?: (reason: string) => void,
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
+  importMap?: {[string]: string},
 };
 
 type ResumeOptions = {
@@ -81,7 +82,11 @@ function createRequestImpl(children: ReactNodeList, options: void | Options) {
   return createRequest(
     children,
     resumableState,
-    createRenderState(resumableState, options ? options.nonce : undefined),
+    createRenderState(
+      resumableState,
+      options ? options.nonce : undefined,
+      options ? options.importMap : undefined,
+    ),
     createRootFormatContext(options ? options.namespaceURI : undefined),
     options ? options.progressiveChunkSize : undefined,
     options ? options.onError : undefined,
@@ -140,6 +145,7 @@ function resumeRequestImpl(
     createRenderState(
       postponedState.resumableState,
       options ? options.nonce : undefined,
+      undefined, // importMap
     ),
     postponedState.rootFormatContext,
     postponedState.progressiveChunkSize,
diff --git a/packages/react-dom/src/server/ReactDOMFizzStaticBrowser.js b/packages/react-dom/src/server/ReactDOMFizzStaticBrowser.js
@@ -38,6 +38,7 @@ type Options = {
   onError?: (error: mixed) => ?string,
   onPostpone?: (reason: string) => void,
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
+  importMap?: {[string]: string},
 };
 
 type StaticResult = {
@@ -81,7 +82,11 @@ function prerender(
     const request = createRequest(
       children,
       resources,
-      createRenderState(resources, undefined),
+      createRenderState(
+        resources,
+        undefined, // nonce
+        options ? options.importMap : undefined,
+      ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
       options ? options.onError : undefined,
diff --git a/packages/react-dom/src/server/ReactDOMFizzStaticEdge.js b/packages/react-dom/src/server/ReactDOMFizzStaticEdge.js
@@ -38,6 +38,7 @@ type Options = {
   onError?: (error: mixed) => ?string,
   onPostpone?: (reason: string) => void,
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
+  importMap?: {[string]: string},
 };
 
 type StaticResult = {
@@ -81,7 +82,11 @@ function prerender(
     const request = createRequest(
       children,
       resources,
-      createRenderState(resources, undefined),
+      createRenderState(
+        resources,
+        undefined, // nonce
+        options ? options.importMap : undefined,
+      ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
       options ? options.onError : undefined,
diff --git a/packages/react-dom/src/server/ReactDOMFizzStaticNode.js b/packages/react-dom/src/server/ReactDOMFizzStaticNode.js
diff --git a/packages/react-dom/src/test-utils/FizzTestUtils.js b/packages/react-dom/src/test-utils/FizzTestUtils.js
