Implement identifierPrefix option for useId

When an `identifierPrefix` option is given, React will add it to the beginning of ids generated by `useId`. The main use case is to avoid conflicts when there are multiple React roots on a single page. The server API already supported an `identifierPrefix` option. It's not only used by `useId`, but also for React-generated ids that are used to stitch together chunks of HTML, among other things. I added a corresponding option to the client. You must pass the same prefix option to both the server and client. Eventually we may make this automatic by sending the prefix from the server as part of the HTML stream.
facebook · Dec 2, 2021 · aca900f · aca900f
1 parent a65ceef
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Showing 20 changed files with 222 additions and 36 deletions.
diff --git a/packages/react-art/src/ReactART.js b/packages/react-art/src/ReactART.js
@@ -66,7 +66,15 @@ class Surface extends React.Component {
 
     this._surface = Mode.Surface(+width, +height, this._tagRef);
 
-    this._mountNode = createContainer(this._surface, LegacyRoot, false, null);
+    this._mountNode = createContainer(
+      this._surface,
+      LegacyRoot,
+      false,
+      null,
+      false,
+      false,
+      '',
+    );
     updateContainer(this.props.children, this._mountNode, this);
   }
 

diff --git a/packages/react-dom/src/__tests__/ReactDOMUseId-test.js b/packages/react-dom/src/__tests__/ReactDOMUseId-test.js
@@ -94,7 +94,7 @@ describe('useId', () => {
 
   function normalizeTreeIdForTesting(id) {
     const [serverClientPrefix, base32, hookIndex] = id.split(':');
-    if (serverClientPrefix === 'r') {
+    if (serverClientPrefix.endsWith('r')) {
       // Client ids aren't stable. For testing purposes, strip out the counter.
       return (
         'CLIENT_GENERATED_ID' +
@@ -569,4 +569,66 @@ describe('useId', () => {
     // Should have hydrated successfully
     expect(span.current).toBe(dehydratedSpan);
   });
+
+  test('identifierPrefix option', async () => {
+    function Child() {
+      const id = useId();
+      return <div>{id}</div>;
+    }
+
+    function App({showMore}) {
+      return (
+        <>
+          <Child />
+          <Child />
+          {showMore && <Child />}
+        </>
+      );
+    }
+
+    await serverAct(async () => {
+      const {pipe} = ReactDOMFizzServer.renderToPipeableStream(<App />, {
+        identifierPrefix: 'custom-prefix-',
+      });
+      pipe(writable);
+    });
+    let root;
+    await clientAct(async () => {
+      root = ReactDOM.hydrateRoot(container, <App />, {
+        identifierPrefix: 'custom-prefix-',
+      });
+    });
+    expect(container).toMatchInlineSnapshot(`
+      <div
+        id="container"
+      >
+        <div>
+          custom-prefix-R:1
+        </div>
+        <div>
+          custom-prefix-R:2
+        </div>
+      </div>
+    `);
+
+    // Mount a new, client-only id
+    await clientAct(async () => {
+      root.render(<App showMore={true} />);
+    });
+    expect(container).toMatchInlineSnapshot(`
+      <div
+        id="container"
+      >
+        <div>
+          custom-prefix-R:1
+        </div>
+        <div>
+          custom-prefix-R:2
+        </div>
+        <div>
+          custom-prefix-r:0
+        </div>
+      </div>
+    `);
+  });
 });
diff --git a/packages/react-dom/src/client/ReactDOMLegacy.js b/packages/react-dom/src/client/ReactDOMLegacy.js
@@ -121,6 +121,7 @@ function legacyCreateRootFromDOMContainer(
     null, // hydrationCallbacks
     false, // isStrictMode
     false, // concurrentUpdatesByDefaultOverride,
+    '', // identiferPrefix
   );
   markContainerAsRoot(root.current, container);
 

diff --git a/packages/react-dom/src/client/ReactDOMRoot.js b/packages/react-dom/src/client/ReactDOMRoot.js
@@ -32,6 +32,7 @@ export type CreateRootOptions = {
   // END OF TODO
   unstable_strictMode?: boolean,
   unstable_concurrentUpdatesByDefault?: boolean,
+  identifierPrefix?: string,
   ...
 };
 
@@ -43,6 +44,7 @@ export type HydrateRootOptions = {
   // Options for all roots
   unstable_strictMode?: boolean,
   unstable_concurrentUpdatesByDefault?: boolean,
+  identifierPrefix?: string,
   ...
 };
 
@@ -158,13 +160,22 @@ export function createRoot(
     null;
   // END TODO
 
-  const isStrictMode = options != null && options.unstable_strictMode === true;
-  let concurrentUpdatesByDefaultOverride = null;
-  if (allowConcurrentByDefault) {
-    concurrentUpdatesByDefaultOverride =
-      options != null && options.unstable_concurrentUpdatesByDefault != null
-        ? options.unstable_concurrentUpdatesByDefault
-        : null;
+  let isStrictMode = false;
+  let concurrentUpdatesByDefaultOverride = false;
+  let identifierPrefix = '';
+  if (options !== null && options !== undefined) {
+    if (options.unstable_strictMode === true) {
+      isStrictMode = true;
+    }
+    if (
+      allowConcurrentByDefault &&
+      options.unstable_concurrentUpdatesByDefault === true
+    ) {
+      concurrentUpdatesByDefaultOverride = true;
+    }
+    if (options.identifierPrefix !== undefined) {
+      identifierPrefix = options.identifierPrefix;
+    }
   }
 
   const root = createContainer(
@@ -174,6 +185,7 @@ export function createRoot(
     hydrationCallbacks,
     isStrictMode,
     concurrentUpdatesByDefaultOverride,
+    identifierPrefix,
   );
   markContainerAsRoot(root.current, container);
 
@@ -217,15 +229,25 @@ export function hydrateRoot(
   // For now we reuse the whole bag of options since they contain
   // the hydration callbacks.
   const hydrationCallbacks = options != null ? options : null;
+  // TODO: Delete this option
   const mutableSources = (options != null && options.hydratedSources) || null;
-  const isStrictMode = options != null && options.unstable_strictMode === true;
-
-  let concurrentUpdatesByDefaultOverride = null;
-  if (allowConcurrentByDefault) {
-    concurrentUpdatesByDefaultOverride =
-      options != null && options.unstable_concurrentUpdatesByDefault != null
-        ? options.unstable_concurrentUpdatesByDefault
-        : null;
+
+  let isStrictMode = false;
+  let concurrentUpdatesByDefaultOverride = false;
+  let identifierPrefix = '';
+  if (options !== null && options !== undefined) {
+    if (options.unstable_strictMode === true) {
+      isStrictMode = true;
+    }
+    if (
+      allowConcurrentByDefault &&
+      options.unstable_concurrentUpdatesByDefault === true
+    ) {
+      concurrentUpdatesByDefaultOverride = true;
+    }
+    if (options.identifierPrefix !== undefined) {
+      identifierPrefix = options.identifierPrefix;
+    }
   }
 
   const root = createContainer(
@@ -235,6 +257,7 @@ export function hydrateRoot(
     hydrationCallbacks,
     isStrictMode,
     concurrentUpdatesByDefaultOverride,
+    identifierPrefix,
   );
   markContainerAsRoot(root.current, container);
   // This can't be a comment node since hydration doesn't work on comment nodes anyway.

diff --git a/packages/react-dom/src/server/ReactDOMServerFormatConfig.js b/packages/react-dom/src/server/ReactDOMServerFormatConfig.js
@@ -64,6 +64,7 @@ export type ResponseState = {
   placeholderPrefix: PrecomputedChunk,
   segmentPrefix: PrecomputedChunk,
   boundaryPrefix: string,
+  idPrefix: string,
   nextSuspenseID: number,
   sentCompleteSegmentFunction: boolean,
   sentCompleteBoundaryFunction: boolean,
@@ -125,6 +126,7 @@ export function createResponseState(
     placeholderPrefix: stringToPrecomputedChunk(idPrefix + 'P:'),
     segmentPrefix: stringToPrecomputedChunk(idPrefix + 'S:'),
     boundaryPrefix: idPrefix + 'B:',
+    idPrefix: idPrefix + 'R:',
     nextSuspenseID: 0,
     sentCompleteSegmentFunction: false,
     sentCompleteBoundaryFunction: false,
@@ -229,6 +231,25 @@ export function assignSuspenseBoundaryID(
   );
 }
 
+export function makeId(
+  responseState: ResponseState,
+  treeId: string,
+  localId: number,
+): string {
+  const idPrefix = responseState.idPrefix;
+
+  let id = idPrefix + treeId;
+
+  // Unless this is the first id at this level, append a number at the end
+  // that represents the position of this useId hook among all the useId
+  // hooks for this fiber.
+  if (localId > 0) {
+    id += ':' + localId.toString(32);
+  }
+
+  return id;
+}
+
 function encodeHTMLTextNode(text: string): string {
   return escapeTextForBrowser(text);
 }

diff --git a/packages/react-dom/src/server/ReactDOMServerLegacyFormatConfig.js b/packages/react-dom/src/server/ReactDOMServerLegacyFormatConfig.js
@@ -34,6 +34,7 @@ export type ResponseState = {
   placeholderPrefix: PrecomputedChunk,
   segmentPrefix: PrecomputedChunk,
   boundaryPrefix: string,
+  idPrefix: string,
   nextSuspenseID: number,
   sentCompleteSegmentFunction: boolean,
   sentCompleteBoundaryFunction: boolean,
@@ -54,6 +55,7 @@ export function createResponseState(
     placeholderPrefix: responseState.placeholderPrefix,
     segmentPrefix: responseState.segmentPrefix,
     boundaryPrefix: responseState.boundaryPrefix,
+    idPrefix: responseState.idPrefix,
     nextSuspenseID: responseState.nextSuspenseID,
     sentCompleteSegmentFunction: responseState.sentCompleteSegmentFunction,
     sentCompleteBoundaryFunction: responseState.sentCompleteBoundaryFunction,
@@ -79,6 +81,7 @@ export {
   getChildFormatContext,
   UNINITIALIZED_SUSPENSE_BOUNDARY_ID,
   assignSuspenseBoundaryID,
+  makeId,
   pushStartInstance,
   pushEndInstance,
   pushStartCompletedSuspenseBoundary,

diff --git a/packages/react-native-renderer/src/ReactFabric.js b/packages/react-native-renderer/src/ReactFabric.js
@@ -213,6 +213,7 @@ function render(
       null,
       false,
       null,
+      '',
     );
     roots.set(containerTag, root);
   }

diff --git a/packages/react-native-renderer/src/ReactNativeRenderer.js b/packages/react-native-renderer/src/ReactNativeRenderer.js
@@ -202,7 +202,15 @@ function render(
   if (!root) {
     // TODO (bvaughn): If we decide to keep the wrapper component,
     // We could create a wrapper for containerTag as well to reduce special casing.
-    root = createContainer(containerTag, LegacyRoot, false, null, false, null);
+    root = createContainer(
+      containerTag,
+      LegacyRoot,
+      false,
+      null,
+      false,
+      null,
+      '',
+    );
     roots.set(containerTag, root);
   }
   updateContainer(element, root, null, callback);

diff --git a/packages/react-native-renderer/src/server/ReactNativeServerFormatConfig.js b/packages/react-native-renderer/src/server/ReactNativeServerFormatConfig.js
@@ -107,6 +107,14 @@ export function assignSuspenseBoundaryID(
   return responseState.nextSuspenseID++;
 }
 
+export function makeId(
+  responseState: ResponseState,
+  treeId: string,
+  localId: number,
+): string {
+  throw new Error('Not implemented');
+}
+
 const RAW_TEXT = stringToPrecomputedChunk('RCTRawText');
 
 export function pushTextInstance(

diff --git a/packages/react-noop-renderer/src/createReactNoop.js b/packages/react-noop-renderer/src/createReactNoop.js
@@ -973,6 +973,8 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
         false,
         null,
         null,
+        false,
+        '',
       );
       return {
         _Scheduler: Scheduler,
@@ -1000,6 +1002,8 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
         false,
         null,
         null,
+        false,
+        '',
       );
       return {
         _Scheduler: Scheduler,

diff --git a/packages/react-reconciler/src/ReactFiberHooks.new.js b/packages/react-reconciler/src/ReactFiberHooks.new.js
@@ -2035,12 +2035,20 @@ export function getIsUpdatingOpaqueValueInRenderPhaseInDEV(): boolean | void {
 function mountId(): string {
   const hook = mountWorkInProgressHook();
 
+  const root = ((getWorkInProgressRoot(): any): FiberRoot);
+  // TODO: In Fizz, id generation is specific to each server config. Maybe we
+  // should do this in Fiber, too? Deferring this decision for now because
+  // there's no other place to store the prefix except for an internal field on
+  // the public createRoot object, which the fiber tree does not currently have
+  // a reference to.
+  const identifierPrefix = root.identifierPrefix;
+
   let id;
   if (getIsHydrating()) {
     const treeId = getTreeId();
 
     // Use a captial R prefix for server-generated ids.
-    id = 'R:' + treeId;
+    id = identifierPrefix + 'R:' + treeId;
 
     // Unless this is the first id at this level, append a number at the end
     // that represents the position of this useId hook among all the useId
@@ -2052,7 +2060,7 @@ function mountId(): string {
   } else {
     // Use a lowercase r prefix for client-generated ids.
     const globalClientId = globalClientIdCounter++;
-    id = 'r:' + globalClientId.toString(32);
+    id = identifierPrefix + 'r:' + globalClientId.toString(32);
   }
 
   hook.memoizedState = id;

diff --git a/packages/react-reconciler/src/ReactFiberHooks.old.js b/packages/react-reconciler/src/ReactFiberHooks.old.js
@@ -2035,12 +2035,20 @@ export function getIsUpdatingOpaqueValueInRenderPhaseInDEV(): boolean | void {
 function mountId(): string {
   const hook = mountWorkInProgressHook();
 
+  const root = ((getWorkInProgressRoot(): any): FiberRoot);
+  // TODO: In Fizz, id generation is specific to each server config. Maybe we
+  // should do this in Fiber, too? Deferring this decision for now because
+  // there's no other place to store the prefix except for an internal field on
+  // the public createRoot object, which the fiber tree does not currently have
+  // a reference to.
+  const identifierPrefix = root.identifierPrefix;
+
   let id;
   if (getIsHydrating()) {
     const treeId = getTreeId();
 
     // Use a captial R prefix for server-generated ids.
-    id = 'R:' + treeId;
+    id = identifierPrefix + 'R:' + treeId;
 
     // Unless this is the first id at this level, append a number at the end
     // that represents the position of this useId hook among all the useId
@@ -2052,7 +2060,7 @@ function mountId(): string {
   } else {
     // Use a lowercase r prefix for client-generated ids.
     const globalClientId = globalClientIdCounter++;
-    id = 'r:' + globalClientId.toString(32);
+    id = identifierPrefix + 'r:' + globalClientId.toString(32);
   }
 
   hook.memoizedState = id;

diff --git a/packages/react-reconciler/src/ReactFiberReconciler.new.js b/packages/react-reconciler/src/ReactFiberReconciler.new.js
@@ -241,6 +241,7 @@ export function createContainer(
   hydrationCallbacks: null | SuspenseHydrationCallbacks,
   isStrictMode: boolean,
   concurrentUpdatesByDefaultOverride: null | boolean,
+  identifierPrefix: string,
 ): OpaqueRoot {
   return createFiberRoot(
     containerInfo,
@@ -249,6 +250,7 @@ export function createContainer(
     hydrationCallbacks,
     isStrictMode,
     concurrentUpdatesByDefaultOverride,
+    identifierPrefix,
   );
 }