📌 React v16.8.6 Patch Release

This release includes a fix for useReducer() bailout and a fix for cross-origin iframes in Safari as well as two new warnings related to contextType.

https://github.com/facebook/react/releases/tag/v16.8.6

💙 Rachel Nabors Joining the React Core Team

Rachel Nabors (rachelnabors) will join the React Core team in May and will be writing docs, building demos, and tending the community. I can’t be more excited!

https://twitter.com/rachelnabors/status/1112699525528018945

🎉 await act(async () => ...)

The recently added act test helper now has support for async functions allowing you await within its callback.

https://github.com/facebook/react/pull/14853

🔥 Experimental React Flare Updates

React Flare (the current name for the internal event API experiments) got a lot more updates this week. Check out this umbrella ticket for an overview of the current status.
Note: This idea is currently in early experimentation phase and might be discarded altogether.

https://github.com/facebook/react/issues/15257

⏱ Rewrite ReactFiberScheduler for Better Integration With Scheduler Package

This PR adds a new ReactFiberScheduler implementation (currently behind a feature flag) that better integrations with the Scheduler package.

https://github.com/facebook/react/pull/15151

🕰 Remove maxDuration

The maxDuration property of React.Suspense, used in Concurrent Mode, was removed. A heuristics with a different mechanism will be used in the future.

https://github.com/facebook/react/pull/15272

🌏 React Docs Localizations Updates

Italian is now complete:
- it.reactjs.org
And the Traditional Chinese documentation website is now online:

https://zh-hant.reactjs.org/

🔧 Fix a Crash in Suspense With findDOMNode

The Core team worked on a fix for a crash when using findDOMNode in a suspended component.

https://github.com/facebook/react/pull/15312

✨ Provide New JSX Transform Target

This PR exposes two new top-level exports: jsx and jsxs. It’s a first step toward the changes described in RFC #107 and is backward compatible to createElement.

https://github.com/facebook/react/pull/15141

🐌 Apply the Just Noticeable Difference to Suspense Timeouts

With this change, the suspended time is increased, based on how long a user has already waiting. Check out the underlying theory on Wikipedia.

https://github.com/facebook/react/pull/15367

🐞 Experimental DevTools Updates

This week, the team continued to work on the new dev tools implementation. Take a look at the current preview.

https://github.com/bvaughn/react-devtools-experimental

⏰ Replace Old Fiber Scheduler with New One

This PR enables the new fiber scheduler implementation as the default one and brings some pretty nice file size savings with it.

https://github.com/facebook/react/pull/15387

🔥 Experimental React Flare Updates

Following the trend of the last week, the team continues to improve the React Flare event experiments.
Note: This idea is currently in early experimentation phase and might be discarded altogether.

https://github.com/facebook/react/issues/15257

🕳 Track Event Time as the Start Time for Suspense

This new suspense model is based on the event time (the time at which the update was triggered).

https://github.com/facebook/react/pull/15358

🥅 React Flare: Add FocusScope

FocusScope was added to the Experimental Event API. It allows trapping focus inside the scope of the event component so that pressing tab at the last element will jump to the first element inside the scope.

https://github.com/facebook/react/pull/15487

🌎 React Docs Localizations Updates

Two new localization repositories were added:
Mongolian: reactjs/mn.reactjs.org
Catalan: reactjs/ca.reactjs.org

The Greek documentation websites went online:
el.reactjs.org

And the Ukrainian localization is complete:
https://uk.reactjs.org/

🔥 Experimental React Flare Updates

Besides the FocusScope addition, there were numerous other updates to the Experimental Event API. The core APIs are now better documented, the propagation system was reworked, event components now have a mount phase, and more.

https://github.com/facebook/react/issues/15257

🐞 Experimental DevTools Updates

Continuing the work on the new DevTools, the last two week bring restoring of selections between reloads, multiple UI changes, new tooltips, and more.

https://github.com/bvaughn/react-devtools-experimental

📹 Add disablePictureInPicture Attribute Support

React now properly sets the disablePictureInPicture attribute for <video> elements thanks to a contribution from Radu-Sebastian Amarie (eek).

https://github.com/facebook/react/pull/15334

🖼 React Native: View Inside Text

After being supported in both iOS and Android, React Core now also supports nesting Views inside Text. Thank you, Adam Comella (rigdern).

https://github.com/facebook/react/pull/15464

🏗 Stop Tracking Bundle Sizes in Repo

A snapshot of the latest bundle sizes will not automatically be stored during the CI run. This makes sure that sizebot compares against the correct sizes.

https://github.com/facebook/react/pull/15404