support React 19.1

Author: mdjastrzebski

README.md

@@ -106,9 +106,9 @@ Configuration options for the test renderer. Many of these options correspond to
 | `transformHiddenInstanceProps` | `({ props, type }: { props: Record<string, unknown>; type: string }) => Record<string, unknown>` | Transforms host instance props when React marks an instance as hidden (for example, while Suspense fallback is shown). Return a new props object instead of mutating the provided one. When provided, hidden instances stay visible in `children` and `toJSON()` output using transformed props. |
 | `identifierPrefix`             | `string`                                                                                         | A string prefix React uses for IDs generated by `useId()`. Useful to avoid conflicts when using multiple roots.                                                                                                                                                                                  |
 | `isStrictMode`                 | `boolean`                                                                                        | Enable React Strict Mode. When enabled, components render twice and effects run twice in development.                                                                                                                                                                                            |
-| `onCaughtError`                | `(error: unknown, errorInfo: { componentStack: string }) => void`                                | Callback called when React catches an error in an Error Boundary. Called with the error caught by the Error Boundary and an errorInfo object containing the component stack.                                                                                                                     |
-| `onUncaughtError`              | `(error: unknown, errorInfo: { componentStack: string }) => void`                                | Callback called when an error is thrown and not caught by an Error Boundary. Called with the error that was thrown and an errorInfo object containing the component stack.                                                                                                                       |
-| `onRecoverableError`           | `(error: unknown, errorInfo: { componentStack: string }) => void`                                | Callback called when React automatically recovers from errors. Called with an error React throws and an errorInfo object containing the component stack. Some recoverable errors may include the original error cause as `error.cause`.                                                          |
+| `onCaughtError`                | `(error: unknown, errorInfo: { componentStack?: string }) => void`                               | Callback called when React catches an error in an Error Boundary. Called with the error caught by the Error Boundary and an errorInfo object containing the component stack.                                                                                                                     |
+| `onUncaughtError`              | `(error: unknown, errorInfo: { componentStack?: string }) => void`                               | Callback called when an error is thrown and not caught by an Error Boundary. Called with the error that was thrown and an errorInfo object containing the component stack.                                                                                                                       |
+| `onRecoverableError`           | `(error: unknown, errorInfo: { componentStack?: string }) => void`                               | Callback called when React automatically recovers from errors. Called with an error React throws and an errorInfo object containing the component stack. Some recoverable errors may include the original error cause as `error.cause`.                                                          |
 
 ### `TestInstance` {#test-instance}
 

bun.lock

@@ -51,8 +51,8 @@
     "release": "release-it"
   },
   "dependencies": {
-    "@types/react-reconciler": "~0.31.0",
-    "react-reconciler": "~0.31.0"
+    "@types/react-reconciler": "~0.32.0",
+    "react-reconciler": "~0.32.0"
   },
   "devDependencies": {
     "@eslint/js": "^10.0.1",

package.json

@@ -5,6 +5,7 @@ import { DefaultEventPriority, NoEventPriority } from "react-reconciler/constant
 import { Tag } from "./constants";
 import { mark, measureEnd, measureStart } from "./performance";
 import { TestInstance } from "./test-instance";
+import { REACT_CONTEXT_TYPE } from "./test-utils/react-constants";
 import { formatComponentList } from "./utils";
 
 export type Type = string;
@@ -37,6 +38,8 @@ export type Instance = {
   unstable_fiber: Fiber;
 };
 
+export type FormInstance = Instance;
+
 export type TextInstance = {
   tag: typeof Tag.Text;
   text: string;
@@ -46,21 +49,20 @@ export type TextInstance = {
 };
 
 export type SuspenseInstance = object;
+export type SuspendedState = unknown;
 export type HydratableInstance = object;
 export type PublicInstance = object | null;
-export type UpdatePayload = unknown;
 export type ChildSet = unknown;
 export type TimeoutHandle = unknown;
 export type NoTimeout = unknown;
+export type TransitionStatus = unknown;
 
 type HostContext = {
   type: string;
   isInsideText: boolean;
   config: ReconcilerConfig;
 };
 
-// Newer react-reconciler builds expect these event-related host config methods at runtime,
-// but the published @types/react-reconciler package may lag behind and omit them.
 type ExtendedHostConfig = ReactReconciler.HostConfig<
   Type,
   Props,
@@ -69,17 +71,14 @@ type ExtendedHostConfig = ReactReconciler.HostConfig<
   TextInstance,
   SuspenseInstance,
   HydratableInstance,
+  FormInstance,
   PublicInstance,
   HostContext,
-  UpdatePayload,
   ChildSet,
   TimeoutHandle,
-  NoTimeout
-> & {
-  trackSchedulerEvent?: () => void;
-  resolveEventType?: () => null | string;
-  resolveEventTimeStamp?: () => number;
-};
+  NoTimeout,
+  TransitionStatus
+>;
 
 const nodeToInstanceMap = new WeakMap<object, Instance>();
 
@@ -709,8 +708,6 @@ const hostConfig: ExtendedHostConfig = {
    *  be aware that it may change significantly between versions. You're taking on additional maintenance risk by
    * reading from it, and giving up all guarantees if you write something to it.
    */
-  // @ts-expect-error @types/react-reconciler types don't fully match react-reconciler's actual Flow types.
-  // Correctness is verified through tests.
   commitUpdate(
     instance: Instance,
     type: Type,
@@ -856,7 +853,7 @@ const hostConfig: ExtendedHostConfig = {
   },
 
   /**
-   * #### `waitForCommitToBeReady()`
+   * #### `waitForCommitToBeReady(state, timeoutOffset)`
    *
    * This method is called after all `suspendInstance` calls are complete.
    *
@@ -865,8 +862,8 @@ const hostConfig: ExtendedHostConfig = {
    * callback will initiate the commit when called. The return value is a cancellation function that the
    * Reconciler can use to abort the commit.
    */
-  waitForCommitToBeReady(type: Type, _props: Props) {
-    mark("reconciler/waitForCommitToBeReady", { type });
+  waitForCommitToBeReady(_state?: SuspendedState, _timeoutOffset?: number) {
+    mark("reconciler/waitForCommitToBeReady");
 
     return null;
   },
@@ -884,6 +881,14 @@ const hostConfig: ExtendedHostConfig = {
   supportsHydration: false,
 
   NotPendingTransition: null,
+  HostTransitionContext: {
+    $$typeof: REACT_CONTEXT_TYPE,
+    Provider: null as unknown as ReactReconciler.ReactProviderType<TransitionStatus>,
+    Consumer: null as unknown as ReactReconciler.ReactContext<TransitionStatus>,
+    _currentValue: null,
+    _currentValue2: null,
+    _threadCount: 0,
+  } as ReactReconciler.ReactContext<TransitionStatus>,
 
   resetFormInstance(_form: Instance) {
     mark("reconciler/resetFormInstance");

src/reconciler.ts

@@ -21,6 +21,7 @@ const defaultOnCaughtError = (error: unknown, errorInfo: ErrorInfo) => {
 const defaultOnRecoverableError = (error: unknown, errorInfo: ErrorInfo) => {
   console.error("Recoverable error:", error, errorInfo);
 };
+const defaultOnDefaultTransitionIndicator = () => {};
 
 /**
  * Options for configuring the test renderer root.
@@ -63,7 +64,7 @@ export type ErrorHandler = (error: unknown, errorInfo: ErrorInfo) => void;
 
 /** Error information provided to error handlers. */
 export type ErrorInfo = {
-  componentStack: string;
+  componentStack?: string;
 };
 
 /**
@@ -112,10 +113,8 @@ export function createRoot(options?: RootOptions): Root {
     options?.identifierPrefix ?? "",
     options?.onUncaughtError ?? defaultOnUncaughtError,
     options?.onCaughtError ?? defaultOnCaughtError,
-    // @ts-expect-error @types/react-reconciler types don't include onRecoverableError parameter
-    // in the createContainer signature, but react-reconciler's actual Flow types do.
-    // Correctness is verified through tests.
     options?.onRecoverableError ?? defaultOnRecoverableError,
+    defaultOnDefaultTransitionIndicator,
     null, // transitionCallbacks
   );
 

src/renderer.ts

@@ -12,3 +12,6 @@ export const DiscreteEventPriority = 2;
 export const ContinuousEventPriority = 8;
 export const DefaultEventPriority = 32;
 export const IdleEventPriority = 0b0010000000000000000000000000000;
+
+// Source: https://github.com/facebook/react/blob/v19.1.0/packages/shared/ReactSymbols.js
+export const REACT_CONTEXT_TYPE = Symbol.for("react.context");