Migrate to React 19 (#4409)

* Update `react-redux` to 9.1.2

* Run tests against different versions of React during CI

* Remove unnecessary `tick` and `runAllTimers` from `cleanup.test.tsx`

* Remove redundant `act` wrappers around `fireEvent` method calls

- According to latest documentation of `@testing-library/react`, `fireEvent` methods are already wrapped inside `act` calls making manual wrapping unnecessary.

* Workaround issue `userEvent` not working with fake timers

- There currently seems to be an issue involving `sinon` fake timers used by `vitest`, `@testing-library/react` only supporting `jest` fake timers and  `@testing-library/user-event` using `setTimeout` internally to simulate user actions such as button presses. Currently `@testing-library/react` only works with `jest` fake timers, which means if there are any component updates while `sinon` fake timers are running in `vitest` , `@testing-library/react` will not catch it and things start to break.
- To workaround this issue, We have to setup the `user` by calling `userEvent.setup({ delay: null })`. The reason why We do this is because `@testing-library/user-event` uses `setTimeout` internally which cannot be awaited in a test while fake timers are running as it can cause the tests to indefinitely hang. So the current workaround is to disable the `delay` functionality of `userEvent` and prevent it from calling `setTimeout`. We also have to pass in `shouldAdvanceTime: true` to `vi.useFakeTimers()` as it can get around the issue of `@testing-library/react` not tracking `sinon` fake timers in `vitest`.

* Fix test names in `fork.test.ts`

- Fixed test names in `fork.test.ts` which could cause the terminal to flicker in Windows.

* Fix issue with `console` spy inside `buildHooks.test.tsx`

- `.mockReset()` should not be called in spies since it calls `.mockClear()` and returns the implementation to its **initial** form. In this case it was silencing some of the `act` related warnings emitted by `@testing-library/react` which needed to be resolved since they were calling issues. So `.mockReset()` calls on spies need to be changed to `.mockRestore()` calls since `.mockRestore()` restores the implementation to its **original** form.

* Fix `act` related issues in `buildHooks.test.tsx`

* Fix issues related to spies and stubbing environments in `utils.spec.ts`

* Fix `console` spy related issues in `effectScenarios.test.ts`

* Fix `console` spy related issues in `listenerMiddleware.test.ts`

* Fix `console` spy related issues in `createApi.test.ts`

* Fix wrong `test.each` and `describe.each` calls

* Fix `console` spy related issues in `devWarnings.test.tsx`

* Fix `console` spy related issues in `injectEndpoints.test.tsx`

* Fix issue with test names in `queryFn.test.tsx`

* Migrate docs to React 19

* Update `peerDependencies` of toolkit to include React v19

* Update React and React-DOM to the new rc version

* Fix issues related to `console` spies in `createAsyncThunk.test.ts`

* Fix issues related to stubbing envs in `createAsyncThunk.test.ts`

* Fix issues related to `console` spies in `createReducer.test.ts`

* Fix issues related to stubbing envs in `createReducer.test.ts`

* Fix issues related to `console` spies in `createSlice.test.ts`

* Fix issues related to stubbing envs in `createSlice.test.ts`

* Fix issues related to `console` spies in `immutableStateInvariantMiddleware.test.ts`

* Fix issues related to `console` spies in `serializableStateInvariantMiddleware.test.ts`

* Change `.toHaveBeenCalledTimes(1)` to `.toHaveBeenCalledOnce()`

* Change `.toHaveBeenCalledTimes(0)` to `.not.toHaveBeenCalled()`

* Set `@types/react` and `@types/react-dom` to temporary types packages

- We set the `@types/react` and `@types/react-dom` package resolutions to `npm:types-react` and `npm:types-react-dom` according to the React 19 migration guide.

* Add `areErrorsEqual` equality tester

- This was done to make sure `toHaveBeenCalledWith` will fail if we pass in the wrong Error constructor. For example the assertion will now fail if we pass in an `Error` instead of a `TypeError`.

* Fix `console` spy related issues in `fakeBaseQuery.test.tsx`

* Fix `console` spy related issues in `queryFn.test.tsx`

* Remove `satisfies` operators in `queryFn.test.tsx`

* Remove `jest-snapshot` from `resolutions` field

- This was done because it was causing the unit tests in example workspaces to fail.

* Remove `console-testing-library` as it is no longer needed

* Fix minor JSX related type issues

* Bump `jsdom` to version 25.0.1

* Bump `@testing-library/react` to version 16.1.0

* Properly `await` assertion in `tests/fork.test.ts`

* Properly `await` assertion in `src/query/tests/errorHandling.test.tsx`

* Migrate to React 19

* Bump TS version in website

---------

Co-authored-by: Mark Erikson <mark@isquaredsoftware.com>

Author: aryaemami59

.github/workflows/tests.yml

@@ -62,13 +62,27 @@ jobs:
           path: packages/toolkit/package.tgz
 
   test-dist:
-    name: Test against dist
+    name: Run local tests against build artifact (React ${{ matrix.react.version }})
     needs: [build]
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
         node: ['20.x']
+        react:
+          [
+            {
+              version: '^18',
+              types: ^18,
+              react-dom: { version: '^18', types: '^18' },
+            },
+            {
+              version: '^19',
+              types: '^19',
+              react-dom: { version: '^19', types: '^19' },
+            },
+          ]
+
     steps:
       - name: Checkout repo
         uses: actions/checkout@v4
@@ -82,17 +96,23 @@ jobs:
       - name: Install deps
         run: yarn install
 
-      - uses: actions/download-artifact@v4
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
         with:
           name: package
           path: packages/toolkit
 
-      - run: ls -lah
+      - name: Check folder contents
+        run: ls -lah
+
+      - name: Install React ${{ matrix.react.version }} and React-DOM ${{ matrix.react.react-dom.version }}
+        run: yarn up react@${{ matrix.react.version }} react-dom@${{ matrix.react.react-dom.version }} @types/react@${{ matrix.react.types }} @types/react-dom@${{ matrix.react.react-dom.types }}
 
       - name: Install build artifact
         run: yarn workspace @reduxjs/toolkit add $(pwd)/package.tgz
 
-      - run: sed -i -e /@remap-prod-remove-line/d ./tsconfig.base.json
+      - name: Erase path aliases
+        run: sed -i -e /@remap-prod-remove-line/d ./tsconfig.base.json
 
       - name: Run tests, against dist
         env:
@@ -103,7 +123,7 @@ jobs:
         run: rm -rf dist && yarn tsc -p . --moduleResolution Bundler --module ESNext --noEmit false --declaration --emitDeclarationOnly --outDir dist --target ESNext && rm -rf dist
 
   test-types:
-    name: 'Test Types: TS ${{ matrix.ts }}'
+    name: 'Test Types: TS ${{ matrix.ts }} and React ${{ matrix.react.version }}'
 
     needs: [build]
     runs-on: ubuntu-latest
@@ -112,6 +132,20 @@ jobs:
       matrix:
         node: ['20.x']
         ts: ['5.0', '5.1', '5.2', '5.3', '5.4', '5.5']
+        react:
+          [
+            {
+              version: '^18',
+              types: ^18,
+              react-dom: { version: '^18', types: '^18' },
+            },
+            {
+              version: '^19',
+              types: '^19',
+              react-dom: { version: '^19', types: '^19' },
+            },
+          ]
+
     steps:
       - name: Checkout repo
         uses: actions/checkout@v4
@@ -125,6 +159,9 @@ jobs:
       - name: Install deps
         run: yarn install
 
+      - name: Install React ${{ matrix.react.version }} and React-DOM ${{ matrix.react.react-dom.version }}
+        run: yarn up react@${{ matrix.react.version }} react-dom@${{ matrix.react.react-dom.version }} @types/react@${{ matrix.react.types }} @types/react-dom@${{ matrix.react.react-dom.types }}
+
       - name: Install TypeScript ${{ matrix.ts }}
         run: yarn add typescript@${{ matrix.ts }}
 
@@ -139,7 +176,8 @@ jobs:
       - name: Show installed RTK versions
         run: yarn info @reduxjs/toolkit
 
-      - run: sed -i -e /@remap-prod-remove-line/d ./tsconfig.base.json
+      - name: Erase path aliases
+        run: sed -i -e /@remap-prod-remove-line/d ./tsconfig.base.json
 
       - name: Test types
         env:

.yarn/patches/console-testing-library-npm-0.6.1-4d9957d402.patch

@@ -3,7 +3,7 @@
   "devDependencies": {
     "@manaflair/redux-batch": "^1.0.0",
     "@types/nanoid": "^2.1.0",
-    "@types/react": "^18.0",
+    "@types/react": "^19.0.1",
     "async-mutex": "^0.3.2",
     "axios": "^0.20.0",
     "formik": "^2.1.5",

.yarn/patches/console-testing-library__npm_0.3.1.patch

@@ -84,21 +84,30 @@ export const store = configureStore({
 
 // file: index.tsx
 import React from 'react'
-import ReactDOM from 'react-dom'
+import { createRoot } from 'react-dom/client'
 import './index.css'
 import App from './App'
 // highlight-start
 import { store } from './app/store'
 import { Provider } from 'react-redux'
 // highlight-end
 
-ReactDOM.render(
-  // highlight-next-line
-  <Provider store={store}>
-    <App />
-  </Provider>,
-  document.getElementById('root')
-)
+const container = document.getElementById('root')
+
+if (container) {
+  const root = createRoot(container)
+
+  root.render(
+    // highlight-next-line
+    <Provider store={store}>
+      <App />
+    </Provider>,
+  )
+} else {
+  throw new Error(
+    "Root element with ID 'root' was not found in the document. Ensure there is a corresponding HTML element with the ID 'root' in your HTML file.",
+  )
+}
 ```
 
 ### Create a Redux State Slice
@@ -214,18 +223,27 @@ export type RootState = ReturnType<typeof store.getState>
 
 // file: index.tsx noEmit
 import React from 'react'
-import ReactDOM from 'react-dom'
+import { createRoot } from 'react-dom/client'
 import { Counter } from './features/counter/Counter'
 import { store } from './app/store'
 import { Provider } from 'react-redux'
 
-ReactDOM.render(
-  // highlight-next-line
-  <Provider store={store}>
-    <Counter />
-  </Provider>,
-  document.getElementById('root')
-)
+const container = document.getElementById('root')
+
+if (container) {
+  const root = createRoot(container)
+
+  root.render(
+    // highlight-next-line
+    <Provider store={store}>
+      <Counter />
+    </Provider>,
+  )
+} else {
+  throw new Error(
+    "Root element with ID 'root' was not found in the document. Ensure there is a corresponding HTML element with the ID 'root' in your HTML file.",
+  )
+}
 
 // file: features/counter/Counter.tsx
 import React from 'react'

docs/package.json

@@ -150,19 +150,27 @@ export const store = configureStore({
 
 // file: index.tsx
 import * as React from 'react'
-import { render } from 'react-dom'
+import { createRoot } from 'react-dom/client'
 import { Provider } from 'react-redux'
 
 import App from './App'
 import { store } from './store'
 
-const rootElement = document.getElementById('root')
-render(
-  <Provider store={store}>
-    <App />
-  </Provider>,
-  rootElement
-)
+const container = document.getElementById('root')
+
+if (container) {
+  const root = createRoot(container)
+
+  root.render(
+    <Provider store={store}>
+      <App />
+    </Provider>,
+  )
+} else {
+  throw new Error(
+    "Root element with ID 'root' was not found in the document. Ensure there is a corresponding HTML element with the ID 'root' in your HTML file.",
+  )
+}
 ```
 
 ## Use the query in a component

docs/tutorials/quick-start.mdx

@@ -181,7 +181,7 @@ export default function StoreProvider({
   children: React.ReactNode
 }) {
   // highlight-start
-  const storeRef = useRef<AppStore>()
+  const storeRef = useRef<AppStore>(undefined)
   if (!storeRef.current) {
     // Create the store instance the first time this renders
     storeRef.current = makeStore()

docs/tutorials/rtk-query.mdx

@@ -1041,6 +1041,7 @@ configureStore({
 If using Redux-Persist, you should specifically ignore all the action types it dispatches:
 
 ```jsx
+import { createRoot } from 'react-dom/client'
 import { configureStore } from '@reduxjs/toolkit'
 import {
   persistStore,
@@ -1078,14 +1079,23 @@ const store = configureStore({
 
 let persistor = persistStore(store)
 
-ReactDOM.render(
-  <Provider store={store}>
-    <PersistGate loading={null} persistor={persistor}>
-      <App />
-    </PersistGate>
-  </Provider>,
-  document.getElementById('root'),
-)
+const container = document.getElementById('root')
+
+if (container) {
+  const root = createRoot(container)
+
+  root.render(
+    <Provider store={store}>
+      <PersistGate loading={null} persistor={persistor}>
+        <App />
+      </PersistGate>
+    </Provider>,
+  )
+} else {
+  throw new Error(
+    "Root element with ID 'root' was not found in the document. Ensure there is a corresponding HTML element with the ID 'root' in your HTML file.",
+  )
+}
 ```
 
 Additionally, you can purge any persisted state by adding an extra reducer to the specific slice that you would like to clear when calling persistor.purge(). This is especially helpful when you are looking to clear persisted state on a dispatched logout action.

docs/usage/nextjs.mdx

@@ -5,12 +5,12 @@
   "dependencies": {
     "@reduxjs/toolkit": "^1.8.0",
     "@types/node": "^12.0.0",
-    "@types/react": "^18.0.12",
-    "@types/react-dom": "^18.0.5",
+    "@types/react": "^19.0.1",
+    "@types/react-dom": "^19.0.1",
     "clsx": "1.1.1",
-    "react": "^18.1.0",
-    "react-dom": "^18.1.0",
-    "react-redux": "^9.1.0",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
+    "react-redux": "^9.1.2",
     "react-scripts": "5.0.1",
     "typescript": "~4.9"
   },