React

• Add support for the new JSX transform. (@lunaruan in #18299)

React

• Backport support for the new JSX transform to 15.x. (@lunaruan in #18299 and @gaearon in #20024)

React

• Backport support for the new JSX transform to 0.14.x. (@lunaruan in #18299 and @gaearon in #20024)

React DOM

• Fix bug in legacy mode Suspense where effect clean-up functions are not fired. This only affects users who use Suspense for data fetching in legacy mode, which is not technically supported. (@acdlite in #18238)
• Revert warning for cross-component updates that happen inside class render lifecycles (componentWillReceiveProps, shouldComponentUpdate, and so on). (@gaearon in #18330)

Artifacts

• react: https://unpkg.com/react@16.13.1/umd/
• react-art: https://unpkg.com/react-art@16.13.1/umd/
• react-dom: https://unpkg.com/react-dom@16.13.1/umd/
• react-is: https://unpkg.com/react-is@16.13.1/umd/
• react-test-renderer: https://unpkg.com/react-test-renderer@16.13.1/umd/
• scheduler: https://unpkg.com/scheduler@0.19.1/umd/

React

• Warn when a string ref is used in a manner that's not amenable to a future codemod (@lunaruan in #17864)
• Deprecate React.createFactory() (@trueadm in #17878)

React DOM

• Warn when changes in style may cause an unexpected collision (@sophiebits in #14181, #18002)
• Warn when a function component is updated during another component's render phase (@acdlite in #17099)
• Deprecate unstable_createPortal (@trueadm in #17880)
• Fix onMouseEnter being fired on disabled buttons (@AlfredoGJ in #17675)
• Call shouldComponentUpdate twice when developing in StrictMode (@bvaughn in #17942)
• Add version property to ReactDOM (@ealush in #15780)
• Don't call toString() of dangerouslySetInnerHTML (@sebmarkbage in #17773)
• Show component stacks in more warnings (@gaearon in #17922, #17586)

Concurrent Mode (Experimental)

• Warn for problematic usages of ReactDOM.createRoot() (@trueadm in #17937)
• Remove ReactDOM.createRoot() callback params and added warnings on usage (@bvaughn in #17916)
• Don't group Idle/Offscreen work with other work (@sebmarkbage in #17456)
• Adjust SuspenseList CPU bound heuristic (@sebmarkbage in #17455)
• Add missing event plugin priorities (@trueadm in #17914)
• Fix isPending only being true when transitioning from inside an input event (@acdlite in #17382)
• Fix React.memo components dropping updates when interrupted by a higher priority update (@acdlite in #18091)
• Don't warn when suspending at the wrong priority (@gaearon in #17971)
• Fix a bug with rebasing updates (@acdlite and @sebmarkbage in #17560, #17510, #17483, #17480)

Artifacts

• react: https://unpkg.com/react@16.13.0/umd/
• react-art: https://unpkg.com/react-art@16.13.0/umd/
• react-dom: https://unpkg.com/react-dom@16.13.0/umd/
• react-is: https://unpkg.com/react-is@16.13.0/umd/
• react-test-renderer: https://unpkg.com/react-test-renderer@16.13.0/umd/
• scheduler: https://unpkg.com/scheduler@0.19.0/umd/

React DOM

• Fix passive effects (useEffect) not being fired in a multi-root app. (@acdlite in #17347)

React Is

• Fix lazy and memo types considered elements instead of components (@bvaughn in #17278)

Artifacts

• react: https://unpkg.com/react@16.12.0/umd/
• react-art: https://unpkg.com/react-art@16.12.0/umd/
• react-dom: https://unpkg.com/react-dom@16.12.0/umd/
• react-is: https://unpkg.com/react-is@16.12.0/umd/
• react-test-renderer: https://unpkg.com/react-test-renderer@16.12.0/umd/
• scheduler: https://unpkg.com/scheduler@0.18.0/umd/

React DOM

• Fix mouseenter handlers from firing twice inside nested React containers. @yuanoook in #16928
• Remove unstable_createRoot and unstable_createSyncRoot experimental APIs. (These are available in the Experimental channel as createRoot and createSyncRoot.) (@acdlite in #17088)

Artifacts

• react: https://unpkg.com/react@16.11.0/umd/
• react-art: https://unpkg.com/react-art@16.11.0/umd/
• react-dom: https://unpkg.com/react-dom@16.11.0/umd/
• react-is: https://unpkg.com/react-is@16.11.0/umd/
• react-test-renderer: https://unpkg.com/react-test-renderer@16.11.0/umd/
• scheduler: https://unpkg.com/scheduler@0.17.0/umd/

React DOM

• Fix regression in react-native-web by restoring order of arguments in event plugin extractors (@necolas in #16978)

Artifacts

• react: https://unpkg.com/react@16.10.2/umd/
• react-art: https://unpkg.com/react-art@16.10.2/umd/
• react-dom: https://unpkg.com/react-dom@16.10.2/umd/
• react-is: https://unpkg.com/react-is@16.10.2/umd/
• react-test-renderer: https://unpkg.com/react-test-renderer@16.10.2/umd/
• scheduler: https://unpkg.com/scheduler@0.16.2/umd/

React DOM

• Fix regression in Next.js apps by allowing Suspense mismatch during hydration to silently proceed (@sebmarkbage in #16943)

React DOM

• Fix edge case where a hook update wasn't being memoized. (@sebmarkbage in #16359)
• Fix heuristic for determining when to hydrate, so we don't incorrectly hydrate during an update. (@sebmarkbage in #16739)
• Clear additional fiber fields during unmount to save memory. (@trueadm in #16807)
• Fix bug with required text fields in Firefox. (@halvves in #16578)
• Prefer Object.is instead of inline polyfill, when available. (@ku8ar in #16212)
• Fix bug when mixing Suspense and error handling. (@acdlite in #16801)

Scheduler (Experimental)

• Improve queue performance by switching its internal data structure to a min binary heap. (@acdlite in #16245)
• Use postMessage loop with short intervals instead of attempting to align to frame boundaries with requestAnimationFrame. (@acdlite in #16214)

useSubscription

• Avoid tearing issue when a mutation happens and the previous update is still in progress. (@bvaughn in #16623)

Artifacts

• react: https://unpkg.com/react@16.10.0/umd/
• react-art: https://unpkg.com/react-art@16.10.0/umd/
• react-dom: https://unpkg.com/react-dom@16.10.0/umd/
• react-is: https://unpkg.com/react-is@16.10.0/umd/
• react-test-renderer: https://unpkg.com/react-test-renderer@16.10.0/umd/
• scheduler: https://unpkg.com/scheduler@0.16.0/umd/