v8.1.3

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v8.1.2

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This version changes imports from the React package to namespace imports so the package can safely be imported in React Server Components as long as you don't actually use it - this is for example important if you want to use the React-specifc createApi function from Redux Toolkit.

Some other changes:

• The behaviour of the "React Context Singletons" from 8.1.1 has been adjusted to also work if you have multiple React instances of the same version (those will now be separated) and if you are in an environment without globalThis (in this case it will fall back to the previous behaviour).
• We do no longer use Proxies, which should help with some very outdated consumers, e.g. smart TVs, that cannot even polyfill Proxies.

Full Changelog: reduxjs/react-redux@v8.1.1...v8.1.2

v8.1.1

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This bugfix release tweaks the recent lazy context setup logic to ensure a single React context instance per React version, and removes the recently added RTK peerdep to fix an issue with Yarn workspaces.

Changelog

React Context Singletons

React Context has always relied on reference identity. If you have two different copies of React or a library in a page, that can cause multiple versions of a context instance to be created, leading to problems like the infamous "Could not find react-redux context" error.

In v8.1.0, we reworked the internals to lazily create our single ReactReduxContext instance to avoid issues in a React Server Components environment.

This release further tweaks that to stash a single context instance per React version found in the page, thus hopefully avoiding the "multiple copies of the same context" error in the future.

What's Changed

• fix: fix typescript error on non exported type by @​luzzif in https://github.com/reduxjs/react-redux/pull/2034
• create singleton context by React version by @​phryneas in https://github.com/reduxjs/react-redux/pull/2039
• remove RTK peerDep by @​markerikson in 44fc725

Full Changelog: reduxjs/react-redux@v8.1.0...v8.1.1

v8.1.0

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This feature release adds new development-mode safety checks for common errors (like poorly-written selectors), adds a workaround to fix crash errors when React-Redux hooks are imported into React Server Component files, and updates our hooks API docs page with improved explanations and updated links.

Changelog

Development Mode Checks for useSelector

We've had a number of users tell us over time that it's common to accidentally write selectors that have bad behavior and cause performance issues. The most common causes of this are either selectors that unconditionally return a new reference (such as state => state.todos.map() without any memoization ), or selectors that actually return the entire root state ( state => state ).

We've updated useSelector to add safety checks in development mode that warn if these incorrect behaviors are detected:

• Selectors will be called twice with the same inputs, and useSelector will warn if the results are different references
• useSelector will warn if the selector result is actually the entire root state

By default, these checks only run once the first time useSelector is called. This should provide a good balance between detecting possible issues, and keeping development mode execution performant without adding many unnecessary extra selector calls.

If you want, you can configure this behavior globally by passing the enum flags directly to <Provider>, or on a per-useSelector basis by passing an options object as the second argument:

// Example: globally configure the root state "noop" check to run every time
<Provider store={store} noopCheck="always">
  {children}
</Provider>

// Example: configure `useSelector` to specifically run the reference checks differently:
function Component() {
  // Disable check entirely for this selector
  const count = useSelector(selectCount, { stabilityCheck: 'never' })
  // run once (default)
  const user = useSelector(selectUser, { stabilityCheck: 'once' })
  // ...
}

This goes along with the similar safety checks we've added to Reselect v5 alpha as well.

Context Changes

We're still trying to work out how to properly use Redux and React Server Components together. One possibility is using RTK Query's createApi to define data fetching endpoints, and using the generated thunks to fetch data in RSCs, but it's still an open question.

However, users have reported that merely importing any React-Redux API in an RSC file causes a crash, because React.createContext is not defined in RSC files. RTKQ's React-specific createApi entry point imports React-Redux, so it's been unusable in RSCs.

This release adds a workaround to fix that issue, by using a proxy wrapper around our singleton ReactReduxContext instance and lazily creating that instance on demand. In testing, this appears to both continue to work in all unit tests, and fixes the import error in an RSC environment. We'd appreciate further feedback in case this change does cause any issues for anyone!

We've also tweaked the internals of the hooks to do checks for correct <Provider> usage when using a custom context, same as the default context checks.

Docs Updates

We've cleaned up some of the Hooks API reference page, and updated links to the React docs.

What's Changed

• check for Provider even when using custom context by @​EskiMojo14 in https://github.com/reduxjs/react-redux/pull/1990
• Add a stability check, to see if selector returns stable result when called with same parameters. by @​EskiMojo14 in https://github.com/reduxjs/react-redux/pull/2000
• Add an E2E-ish test that verifies behavior when imported into RSCs by @​markerikson in https://github.com/reduxjs/react-redux/pull/2030
• lazily create Context for RSC compat by @​phryneas in https://github.com/reduxjs/react-redux/pull/2025
• Add warning for selectors that return the entire state by @​EskiMojo14 in https://github.com/reduxjs/react-redux/pull/2022

Full Changelog: reduxjs/react-redux@v8.0.7...v8.1.0

v8.0.7

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This release updates the peer dependencies to accept Redux Toolkit, and accept the ongoing RTK and Redux core betas as valid peer deps.

Note: These changes were initially in 8.0.6, but that had a typo in the peer deps that broke installation. Sorry!

What's Changed

• Bump Redux peer deps to accept 5.0 betas, and bump RTK dev dep by @​markerikson in https://github.com/reduxjs/react-redux/pull/2017
• d45204f : Fix broken RTK peer dep

Full Changelog: reduxjs/react-redux@v8.0.5...v8.0.7

v8.0.6

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~~This release updates the peer dependencies to accept Redux Toolkit, and accept the ongoing RTK and Redux core betas as valid peer deps.~~

This release has a peer deps typo that breaks installation - please use 8.0.7 instead !

What's Changed

• Bump Redux peer deps to accept 5.0 betas, and bump RTK dev dep by @​markerikson in https://github.com/reduxjs/react-redux/pull/2017

Full Changelog: reduxjs/react-redux@v8.0.5...v8.0.6

v8.0.5

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This release fixes a few minor TS issues.

What's Changed

• Provider: pass state (S) generic through to ProviderProps by @​OliverJAsh in https://github.com/reduxjs/react-redux/pull/1960
• wrap equalityFn type in NoInfer by @​phryneas in https://github.com/reduxjs/react-redux/pull/1965
• Fix wrapped component prop types when passing nullish mapDispatchToProps by @​marconi1992 in https://github.com/reduxjs/react-redux/pull/1928

Full Changelog: reduxjs/react-redux@v8.0.4...v8.0.5

v8.0.4

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This patch release fixes some minor TS types issues, and updates the rarely-used areStatesEqual option for connect to now pass through ownProps for additional use in determining which pieces of state to compare if desired.

Note: 8.0.3 was accidentally published without one of these fixes. Use 8.0.4 instead.

Changelog

TS Fixes

We've fixed an import of React that caused issues with the allowSyntheticDefaultImports TS compiler flag in user projects.

connect already accepted a custom context instance as props.context, and had runtime checks in case users were passing through a real value with app data as props.context instead. However, the TS types did not handle that case, and this would fail to compile. If your own component expects props.context with actual data, connect's types now use that type instead.

The ConnectedProps<T> type had a mismatch with React's built-in React.ComponentProps<Component> type, and that should now work correctly.

Other Changes

The areStatesEqual option to connect now receives ownProps as well, in case you need to make a more specific comparison with certain sections of state.

The new signature is:

{
  areStatesEqual?: (
    nextState: State,
    prevState: State,
    nextOwnProps: TOwnProps,
    prevOwnProps: TOwnProps
  ) => boolean
}

What's Changed

• Don't require allowSyntheticDefaultImports: true by @​apepper in https://github.com/reduxjs/react-redux/pull/1924
• Fixed type issue with ComponentProps from older @types/react by @​Andarist in https://github.com/reduxjs/react-redux/pull/1956
• connect: pass ownProps to areStatesEqual by @​jspurlin in https://github.com/reduxjs/react-redux/pull/1951
• Omit built-in context prop if user component props include context by @​markerikson in https://github.com/reduxjs/react-redux/pull/1958

Full Changelog: reduxjs/react-redux@v8.0.2...v8.0.4

v8.0.3

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This release was accidentally published without an intended fix - please use v8.0.4 instead

v8.0.2

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This patch release tweaks the behavior of connect to print a one-time warning when the obsolete pure option is passed in, rather than throwing an error. This fixes crashes caused by libraries such as react-beautiful-dnd continuing to pass in that option (unnecessarily) to React-Redux v8.

What's Changed

• Show warning instead of throwing error that pure option has been removed by @​ApacheEx in https://github.com/reduxjs/react-redux/pull/1922

Full Changelog: reduxjs/react-redux@v8.0.1...v8.0.2

v8.0.1

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This release fixes an incorrect internal import of our Subscription type, which was causing TS compilation errors in some user projects. We've also listed @types/react-dom as an optional peerDep. There are no runtime changes in this release.

What's Changed

• Add optional peer dependency on @​types/react-dom by @​Methuselah96 in https://github.com/reduxjs/react-redux/pull/1904
• fix(ts): incorrect import of Subscription causes noImplicitAny error by @​vicrep in https://github.com/reduxjs/react-redux/pull/1910

Full Changelog: reduxjs/react-redux@v8.0.0...v8.0.1

v8.0.0

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This major version release updates useSelector, connect, and <Provider> for compatibility with React 18, rewrites the React-Redux codebase to TypeScript (obsoleting use of @types/react-redux), modernizes build output, and removes the deprecated connectAdvanced API and the pure option for connect.

npm i react-redux@latest

yarn add react-redux@latest

Overview, Compatibility, and Migration

Our public API is still the same ( <Provider>, connect and useSelector/useDispatch), but we've updated the internals to use the new useSyncExternalStore hook from React. React-Redux v8 is still compatible with all versions of React that have hooks (16.8+, 17.x, and 18.x; React Native 0.59+), and should just work out of the box.

In most cases, it's very likely that the only change you will need to make is bumping the package version to "react-redux": "^8.0".

If you are using the rarely-used connectAdvanced API, you will need to rewrite your code to avoid that, likely by using the hooks API instead. Similarly, the pure option for connect has been removed.

If you are using Typescript, React-Redux is now written in TS and includes its own types. You should remove any dependencies on @types/react-redux.

While not directly tied to React-Redux, note that the recently updated @types/react@18 major version has changed component definitions to remove having children as a prop by default. This causes errors if you have multiple copies of @types/react in your project. To fix this, tell your package manager to resolve @types/react to a single version. Details:

React issue #​24304: React 18 types broken since release

Additionally, please see the React post on How to Ugprade to React 18 for details on how to migrate existing apps to correctly use React 18 and take advantage of its new features.

Changelog

React 18 Compatibility

React-Redux now requires the new useSyncExternalStore API in React 18. By default, it uses the "shim" package which backfills that API in earlier React versions, so React-Redux v8 is compatible with all React versions that have hooks (16.8+, and React Native 0.59+) as its acceptable peer dependencies.

We'd especially like to thank the React team for their extensive support and cooperation during the useSyncExternalStore development effort. They specifically designed useSyncExternalStore to support the needs and use cases of React-Redux, and we used React-Redux v8 as a testbed for how useSyncExternalStore would behave and what it needed to cover. This in turn helped ensure that useSyncExternalStore would be useful and work correctly for other libraries in the ecosystem as well.

Our performance benchmarks show parity with React-Redux v7.2.5 for both connect and useSelector, so we do not anticipate any meaningful performance regressions.

useSyncExternalStore and Bundling

The useSyncExternalStore shim is imported directly in the main entry point, so it's always included in bundles even if you're using React 18. This adds roughly 600 bytes minified to your bundle size.

If you are using React 18 and would like to avoid that extra bundle cost, React-Redux now has a new /next entry point. This exports the exact same APIs, but directly imports useSyncExternalStore from React itself, and thus avoids including the shim. You can alias "react-redux": "react-redux/next" in your bundler to use that instead.

SSR and Hydration

React 18 introduces a new hydrateRoot method for hydrating the UI on the client in Server-Side Rendering usage. As part of that, the useSyncExternalStore API requires that we pass in an alternate state value other than what's in the actual Redux store, and that alternate value will be used for the entire initial hydration render to ensure the initial rehydrated UI is an exact match for what was rendered on the server. After the hydration render is complete, React will then apply any additional changes from the store state in a follow-up render.

React-Redux v8 supports this by adding a new serverState prop for <Provider>. If you're using SSR, you should pass your serialized state to <Provider> to ensure there are no hydration mismatch errors:

import { hydrateRoot } from 'react-dom/client'
import { configureStore } from '@​reduxjs/toolkit'
import { Provider } from 'react-redux'

const preloadedState = window.__PRELOADED_STATE__

const clientStore = configureStore({
  reducer: rootReducer,
  preloadedState,
})

hydrateRoot(
  document.getElementById('root'),
  <Provider store={clientStore} serverState={preloadedState}>
    <App />
  </Provider>
)

TypeScript Migration and Support

The React-Redux library source has always been written in plain JS, and the community maintained the TS typings separately as @types/react-redux.

We've (finally!) migrated the React-Redux codebase to TypeScript, using the existing typings as a starting point. This means that the @types/react-redux package is no longer needed, and you should remove that as a dependency.

Note Please ensure that any installed copies of redux and @types/react are de-duped. You are also encouraged to update to the latest versions of Redux Toolkit (1.8.1+) or Redux (4.1.2), to ensure consistency between installed types and avoid problems from types mismatches.

We've tried to maintain the same external type signatures as much as possible. If you do see any compile problems, please file issues with any apparent TS-related problems so we can review them.

The TS migration was a great collaborative effort, with many community members contributing migrated files. Thank you to everyone who helped out!

In addition to the "pre-typed" TypedUseSelectorHook, there's now also a Connect<State = unknown> type that can be used as a "pre-typed" version of connect as well.

As part of the process, we also updated the repo to use Yarn 3, copied the typetests files from DefinitelyTyped and expanded them, and improved our CI setup to test against multiple TS versions.

Removal of the DefaultRootState type

The @types/react-redux package, which has always been maintained by the community, included a DefaultRootState interface that was intended for use with TS's "module augmentation" capability. Both connect and useSelector used this as a fallback if no state generic was provided. When we migrated React-Redux to TS, we copied over all of the types from that package as a starting point.

However, the Redux team specifically considers use of a globally augmented state type to be an anti-pattern. Instead, we direct users to extract the RootState and AppDispatch types from the store setup, and create pre-typed versions of the React-Redux hooks for use in the app.

Now that React-Redux itself is written in TS, we've opted to remove the DefaultRootState type entirely. State generics now default to unknown instead.

Technically the module augmentation approach can still be done in userland, but we discourage this practice.

Modernized Build Output

We've always targeted ES5 syntax in our published build artifacts as the lowest common denominator. Even the "ES module" artifacts with import/export keywords still were compiled to ES5 syntax otherwise.

With IE11 now effectively dead and many sites no longer supporting it, we've updated our build tooling to target a more modern syntax equivalent to ES2017, which shrinks the bundle size slightly.

If you still need to support ES5-only environments, please compile your own dependencies as needed for your target environment.

Removal of Legacy APIs

We announced in 2019 that the legacy connectAdvanced API would be removed in the next major version, as it was rarely used, added internal complexity, and was also basically irrelevant with the introduction of hooks. As promised, we've removed that API.

We've also removed the pure option for connect, which forced components to re-render regardless of whether props/state had actually changed if it was set to false. This option was needed in some cases in the early days of the React ecosystem, when components sometimes relied on external mutable data sources that could change outside of rendering. Today, no one writes components that way, the option was barely used, and React 18's useSyncExternalStore strictly requires immutable updates. So, we've removed the pure flag.

Given that both of these options were almost never used, this shouldn't meaningfully affect anyone.

Changes

Due to the TS migration effort and number of contributors, this list covers just the major changes:

• Integrate TypeScript port by @​markerikson in https://github.com/reduxjs/react-redux/pull/1739
• Initial experimental React 18 compat prototyping by @​markerikson in https://github.com/reduxjs/react-redux/pull/1808
• Fix compatibility with React 18 strict effects by @​markerikson in https://github.com/reduxjs/react-redux/pull/1817
• Update to latest React 18 alpha dependencies by @​markerikson in https://github.com/reduxjs/react-redux/pull/1834
• Port remaining v7 typetests and improve v8 types by @​markerikson in https://github.com/reduxjs/react-redux/pull/1855
• Add initial SSR support for React 18 and React-Redux v8 by @​markerikson in https://github.com/reduxjs/react-redux/pull/1835
• test: Adjust type tests to be compatible with React 18 typings by @​eps1lon in https://github.com/reduxjs/react-redux/pull/1868
• Switch back to Subscription in useSelector to fix unsubscribe perf by @​markerikson in https://github.com/reduxjs/react-redux/pull/1870
• Cleanup more code after pure removal by @​Andarist in https://github.com/reduxjs/react-redux/pull/1859
• Swap useSyncExternalStore shim behavior and update React deps by @​markerikson in https://github.com/reduxjs/react-redux/pull/1884
• Remove DefaultRootState type by @​markerikson in https://github.com/reduxjs/react-redux/pull/1887
• Add SSR test for serverState behavior by @​markerikson in https://github.com/reduxjs/react-redux/pull/1888
• Cleanup internal types in selectorFactory.ts by @​Methuselah96 in https://github.com/reduxjs/react-redux/pull/1889
• Remove ts-ignore for initMergeProps by @​Methuselah96 in https://github.com/reduxjs/react-redux/pull/1891
• fix(deps): add optional peer deps into peerDependencies by @​kyletsang in https://github.com/reduxjs/react-redux/pull/1893
• Update peer deps for v8 by @​markerikson in https://github.com/reduxjs/react-redux/pull/1895
• Port DT fix for dispatchProp arg in mergeProps by @​markerikson in https://github.com/reduxjs/react-redux/pull/1897
• Update docs for v8 final by @​markerikson in https://github.com/reduxjs/react-redux/pull/1902