⛑ Add Feature Flag to Disable Yielding

A new feature flag was added that allows debug builds to disable yielding in Concurrent Mode.
https://github.com/facebook/react/pull/15119

📌 React v16.8.5 Patch Release

This release includes a improved warnings and support for newer features in the shallow renderer.
https://github.com/facebook/react/releases/tag/v16.8.5

🕹 Internal Event API Experiments Updates

This week added more parts to the internal event API experiments including event component responder surfaces and SSR support.

https://github.com/facebook/react/pull/15179

💃 Dancing Between State and Effects

James Long (jlongster) started a discussion about ways to combine effects and state changes. Feedback welcome!

https://github.com/facebook/react/issues/15240

🎚 Enabled warnAboutDeprecatedLifecycles

React will, starting with the next minor version, warn when deprecated lifecycle methods are used. You can learn more about this deprecation in this blog post.

https://reactjs.org/blog/2018/03/27/update-on-async-rendering.html

https://github.com/facebook/react/pull/15186

🌍 Turkish Localization Completed

The Turkish localization is now complete, making it the eight complete localization.

https://tr.reactjs.org/

⚠️ Warn About Async Infinite useEffect loop

This PR adds a warning for an infinite useEffect loop caused by calling setState without defining a dependency array or one of the dependencies changes on every render.

https://github.com/facebook/react/pull/15180

📌 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