(instance = current)} />
-+
{instance = current}} />
-```
-
-The original code returned the instance of the `HTMLDivElement` and TypeScript wouldn't know if this was supposed to be a cleanup function or not.
-
-### `useRef` requires an argument {/*useref-requires-argument*/}
-
-_This change is included in the `react-19` codemod preset as [`refobject-defaults`](https://github.com/eps1lon/types-react-codemod/#refobject-defaults)._
-
-A long-time complaint of how TypeScript and React work has been `useRef`. We've changed the types so that `useRef` now requires an argument. This significantly simplifies its type signature. It'll now behave more like `createContext`.
-
-```ts
-// @ts-expect-error: Expected 1 argument but saw none
-useRef();
-// Passes
-useRef(undefined);
-// @ts-expect-error: Expected 1 argument but saw none
-createContext();
-// Passes
-createContext(undefined);
-```
-
-This now also means that all refs are mutable. You'll no longer hit the issue where you can't mutate a ref because you initialised it with `null`:
-
-```ts
-const ref = useRef(null);
-
-// Cannot assign to 'current' because it is a read-only property
-ref.current = 1;
-```
-
-`MutableRef` is now deprecated in favor of a single `RefObject` type which `useRef` will always return:
-
-```ts
-interface RefObject {
- current: T
-}
-
-declare function useRef: RefObject
-```
-
-`useRef` still has a convenience overload for `useRef(null)` that automatically returns `RefObject`. To ease migration due to the required argument for `useRef`, a convenience overload for `useRef(undefined)` was added that automatically returns `RefObject`.
-
-Check out [[RFC] Make all refs mutable](https://github.com/DefinitelyTyped/DefinitelyTyped/pull/64772) for prior discussions about this change.
-
-### Changes to the `ReactElement` TypeScript type {/*changes-to-the-reactelement-typescript-type*/}
-
-_This change is included in the [`react-element-default-any-props`](https://github.com/eps1lon/types-react-codemod#react-element-default-any-props) codemod._
-
-The `props` of React elements now default to `unknown` instead of `any` if the element is typed as `ReactElement`. This does not affect you if you pass a type argument to `ReactElement`:
-
-```ts
-type Example2 = ReactElement<{ id: string }>["props"];
-// ^? { id: string }
-```
-
-But if you relied on the default, you now have to handle `unknown`:
-
-```ts
-type Example = ReactElement["props"];
-// ^? Before, was 'any', now 'unknown'
-```
-
-You should only need it if you have a lot of legacy code relying on unsound access of element props. Element introspection only exists as an escape hatch, and you should make it explicit that your props access is unsound via an explicit `any`.
-
-### The JSX namespace in TypeScript {/*the-jsx-namespace-in-typescript*/}
-This change is included in the `react-19` codemod preset as [`scoped-jsx`](https://github.com/eps1lon/types-react-codemod#scoped-jsx)
-
-A long-time request is to remove the global `JSX` namespace from our types in favor of `React.JSX`. This helps prevent pollution of global types which prevents conflicts between different UI libraries that leverage JSX.
-
-You'll now need to wrap module augmentation of the JSX namespace in `declare module "....":
-
-```diff
-// global.d.ts
-+ declare module "react" {
- namespace JSX {
- interface IntrinsicElements {
- "my-element": {
- myElementProps: string;
- };
- }
- }
-+ }
-```
-
-The exact module specifier depends on the JSX runtime you specified in the `compilerOptions` of your `tsconfig.json`:
-
-- For `"jsx": "react-jsx"` it would be `react/jsx-runtime`.
-- For `"jsx": "react-jsxdev"` it would be `react/jsx-dev-runtime`.
-- For `"jsx": "react"` and `"jsx": "preserve"` it would be `react`.
-
-### Better `useReducer` typings {/*better-usereducer-typings*/}
-
-`useReducer` now has improved type inference thanks to [@mfp22](https://github.com/mfp22).
-
-However, this required a breaking change where `useReducer` doesn't accept the full reducer type as a type parameter but instead either needs none (and rely on contextual typing) or needs both the state and action type.
-
-The new best practice is _not_ to pass type arguments to `useReducer`.
-```diff
-- useReducer>(reducer)
-+ useReducer(reducer)
-```
-This may not work in edge cases where you can explicitly type the state and action, by passing in the `Action` in a tuple:
-```diff
-- useReducer>(reducer)
-+ useReducer(reducer)
-```
-If you define the reducer inline, we encourage to annotate the function parameters instead:
-```diff
-- useReducer>((state, action) => state)
-+ useReducer((state: State, action: Action) => state)
-```
-This is also what you'd also have to do if you move the reducer outside of the `useReducer` call:
-
-```ts
-const reducer = (state: State, action: Action) => state;
-```
-
-## Changelog {/*changelog*/}
-
-### Other breaking changes {/*other-breaking-changes*/}
-
-- **react-dom**: Error for javascript URLs in src/href [#26507](https://github.com/facebook/react/pull/26507)
-- **react-dom**: Remove `errorInfo.digest` from `onRecoverableError` [#28222](https://github.com/facebook/react/pull/28222)
-- **react-dom**: Remove `unstable_flushControlled` [#26397](https://github.com/facebook/react/pull/26397)
-- **react-dom**: Remove `unstable_createEventHandle` [#28271](https://github.com/facebook/react/pull/28271)
-- **react-dom**: Remove `unstable_renderSubtreeIntoContainer` [#28271](https://github.com/facebook/react/pull/28271)
-- **react-dom**: Remove `unstable_runWithPrioirty` [#28271](https://github.com/facebook/react/pull/28271)
-- **react-is**: Remove deprecated methods from `react-is` [28224](https://github.com/facebook/react/pull/28224)
-
-### Other notable changes {/*other-notable-changes*/}
-
-- **react**: Batch sync, default and continuous lanes [#25700](https://github.com/facebook/react/pull/25700)
-- **react**: Don't prerender siblings of suspended component [#26380](https://github.com/facebook/react/pull/26380)
-- **react**: Detect infinite update loops caused by render phase updates [#26625](https://github.com/facebook/react/pull/26625)
-- **react-dom**: Transitions in popstate are now synchronous [#26025](https://github.com/facebook/react/pull/26025)
-- **react-dom**: Remove layout effect warning during SSR [#26395](https://github.com/facebook/react/pull/26395)
-- **react-dom**: Warn and don't set empty string for src/href (except anchor tags) [#28124](https://github.com/facebook/react/pull/28124)
-
-We'll publish the full changelog with the stable release of React 19.
-
----
-
-Thanks to [Andrew Clark](https://twitter.com/acdlite), [Eli White](https://twitter.com/Eli_White), [Jack Pope](https://github.com/jackpope), [Jan Kassens](https://github.com/kassens), [Josh Story](https://twitter.com/joshcstory), [Matt Carroll](https://twitter.com/mattcarrollcode), [Noah Lemen](https://twitter.com/noahlemen), [Sophie Alpert](https://twitter.com/sophiebits), and [Sebastian Silbermann](https://twitter.com/sebsilbermann) for reviewing and editing this post.