Hello React Native Community,​

In May 2020 Facebook was the first company to take the GAAD pledge, by doing so they committed to making accessibility a core part of the React Native open source project. Since May, Facebook has spent that time thoughtfully reviewing and documenting accessibility gaps within React Native. So far the gap analysis has surfaced 90 issues, all of which have been translated to GitHub issues.

Overall, we found that React Native APIs provide strong support for accessibility. However, we also found many core components do not yet fully utilize platform accessibility APIs and support is missing for some platform specific features.

The enthusiasm and diversity of contributors have always played a critical role in the development of React Native and these gaps in accessibility are great opportunities for current and new contributors. If you have been interested in contributing to React Native, we encourage you to join us in making React Native more accessible.

To recognize contributors for their effort, when an accessibility issue is closed and attached to a pull request, contributors will get a shout out on Twitter from our community manager. Contributors whose pull requests are accepted into the codebase will be highlighted in our monthly issues update on the React Native blog.

Please join us in making React Native more accessible for everyone.

How you can help:​

• New contributors should read the contribution guide and browse the list of 46 good first issues in the React Native GitHub.

• Contributors interested in issues requiring a bit more effort should visit the project page for Improved React Native Accessibility to see the GitHub issues that need their knowledge of React Native.

• Technical writers interested in updating React Native's documentation to reflect the accessibility gaps being closed should visit the React Native Docs.

• Share this initiative with anyone who may be able to help!

• Follow the GAAD Pledge Open Source Accessibility Community Manager for React Native on Twitter or Facebook to keep up to date on progress.

Today we’re releasing React Native 0.64 that ships with support for Hermes on iOS.

Hermes opt-in on iOS​

Hermes is an open source JavaScript engine optimized for running React Native. It improves performance by decreasing memory utilization, reducing download size and decreasing the time it takes for the app to become usable or “time to interactive” (TTI).

With this release, we are happy to announce that you can now use Hermes to build on iOS as well. To enable Hermes on iOS, set hermes_enabled to true in your Podfile and run pod install .

use_react_native!(
   :path => config[:reactNativePath],
   # to enable hermes on iOS, change `false` to `true` and then install pods
   :hermes_enabled => true
)

Please keep in mind that Hermes support on iOS is still early stage. We are keeping it as an opt-in as we are running further benchmarking. We encourage you to try it on your own applications and let us know how it is working out for you!

Inline Requires enabled by default​

Inline Requires is a Metro configuration option that improves startup time by delaying execution of JavaScript modules until they are used, instead of at startup.

This feature has existed and been recommended for a few years as an opt-in configuration option, listed in the Performance section of our documentation. We are now enabling this option by default for new applications to help people have fast React Native applications without extra configuration.

Inline Requires is a Babel transform that takes module imports and converts them to be inline. As an example, Inline Requires transforms this module import call from being at the top of the file to where it is used.

Before:

import {MyFunction} from 'my-module';

const MyComponent = props => {
  const result = MyFunction();

  return <Text>{result}</Text>;
};

After:

const MyComponent = props => {
  const result = require('my-module').MyFunction();

  return <Text>{result}</Text>;
};

More information about Inline Requires is available in the Performance documentation.

View Hermes traces with Chrome​

Over the last year Facebook has sponsored the Major League Hacking fellowship, supporting contributions to React Native. Jessie Nguyen and Saphal Patro added the ability to use the Performance tab on Chrome DevTools to visualize the execution of your application when it is using Hermes.

For more information, check out the new documentation page.

Hermes with Proxy Support​

We have added Proxy support to Hermes, enabling compatibility with popular community projects like react-native-firebase and mobx. If you have been using these packages you can now migrate to Hermes for your project.

We plan to make Hermes the default JavaScript engine for Android in a coming release so we are working to resolve the remaining issues people have when using Hermes. Please open an issue on the Hermes GitHub repo if there are remaining issues holding back your app from adopting Hermes.

React 17​

React 17 does not include new developer-facing features or major breaking changes. For React Native applications, the main change is a new JSX transform enabling files to no longer need to import React to be able to use JSX.

More information about React 17 is available on the React blog.

Major Dependency Version Changes​

• Dropped Android API levels 16-20. The Facebook app consistently drops support for Android versions with sufficiently low usage. As the Facebook app no longer supports these versions and is React Native’s main testing surface, React Native is dropping support as well.
• Xcode 12 and CocoaPods 1.10 are required
• Minimum Node support bumped from 10 to Node 12
• Flipper bumped to 0.75.1

Thanks​

Thank you to the hundreds of contributors that helped make 0.64 possible! The 0.64 changelog includes all of the changes included in this release.

We’re excited to announce React Native 0.61, which includes a new reloading experience we’re calling Fast Refresh.

Fast Refresh​

When we asked the React Native community about common pain points, one of the top answers was that the “hot reloading” feature was broken. It didn’t work reliably for function components, often failed to update the screen, and wasn’t resilient to typos and mistakes. We heard that most people turned it off because it was too unreliable.

In React Native 0.61, we’re unifying the existing “live reloading” (reload on save) and “hot reloading” features into a single new feature called “Fast Refresh” . Fast Refresh was implemented from scratch with the following principles:

• Fast Refresh fully supports modern React , including function components and Hooks.
• Fast Refresh gracefully recovers after typos and other mistakes, and falls back to a full reload when needed.
• Fast Refresh doesn’t perform invasive code transformations so it’s reliable enough to be on by default.

To see Fast Refresh in action, check out this video:

Give it a try, and let us know what you think! If you prefer, you can turn it off in the Dev Menu (Cmd+D on iOS, Cmd+M or Ctrl+M on Android). Turning it on and off is instant so you can do it any time.

Here are a few Fast Refresh tips:

• Fast Refresh preserves React local state in function components (and Hooks!) by default.
• If you need to reset the React state on every edit, you can add a special // @refresh reset comment to the file with that component.
• Fast Refresh always remounts class components without preserving state. This ensures it works reliably.
• We all make mistakes in the code! Fast Refresh automatically retries rendering after you save a file. You don't need to reload the app manually after fixing a syntax or a runtime error.
• Adding a console.log or a debugger statement during edits is a neat debugging technique.

Please report any issues with Fast Refresh on GitHub, and we’ll look into them.

Other Improvements​

• Fixed use_frameworks! CocoaPods support. In 0.60 we made some updates to integrate CocoaPods by default. Unfortunately, this broke builds using use_frameworks!. This is fixed in 0.61, making it easier to integrate React Native into your iOS projects that require building with dynamic frameworks.
• Add useWindowDimensions Hook. This new Hook automatically provides and subscribes to dimension updates, and can be used instead of the Dimensions API in most cases.
• React was upgraded to 16.9. This version deprecates old names for the UNSAFE _ lifecycle methods, contains improvements to act , and more. See the React 16.9 blog post for an automated migration script and more information.

Breaking Changes​

• Remove React .xcodeproj. In 0.60, we introduced auto-linking support via CocoaPods. We have also integrated CocoaPods into the e2e tests runs, so that from now on, we have a unified standard way of integrating RN into iOS apps. This effectively deprecates the React .xcodeproj support, and the file has been removed starting 0.61. Note: if you use 0.60 auto-linking already, you shouldn't be affected.

Thanks​

Thanks to all of the contributors that helped make 0.61 possible!

To see all the updates, take a look at the 0.61 changelog.

After over 20 pull requests from 6 contributors in the React Native Community, we're excited to launch react-native doctor , a new command to help you out with getting started, troubleshooting and automatically fixing errors with your development environment. The doctor command is heavily inspired by Expo and Homebrew's own doctor command with a pinch of UI inspired by Jest.

Here it is in action:

How it works​

The doctor command currently supports most of the software and libraries that React Native relies on, such as CocoaPods, Xcode and Android SDK. With doctor we'll find issues with your development environment and give you the option to automatically fix them. If doctor is not able to fix an issue, it will display a message and a helpful link explaining how to fix it manually as the following:

Try it now​

The doctor command is available as a part of React Native 0.62. However, you can try it without upgrading yet:

npx @react-native-community/cli doctor

What checks are currently supported​

doctor currently supports the following checks:

• Node.js (>= 8.3)
• yarn (>= 1.10)
• npm (>= 4)
• Watchman (>= 4), used for watching changes in the filesystem when in development mode.

Specific to the Android environment:

• Android SDK (>= 26), the software runtime for Android.
• Android NDK (>= 19), the native development toolkit for Android.
• ANDROID_HOME , environment variable required by the Android SDK setup.

And to the iOS environment:

• Xcode (>= 10), IDE for developing, building and shipping iOS applications.
• CocoaPods, library dependency management tool for iOS applications.
• ios-deploy (optional), library used internally by the CLI to install applications on a physical iOS device.

Thanks​

Huge thanks for the React Native Community for working on this, in particular @thymikee, @thib92, @jmeistrich, @tido64 and @rickhanlonii.

Today we’re releasing React Native version 0.62 which includes support for Flipper by default.

This release comes in the midst of a global pandemic. We’re releasing this version today to respect the work of hundreds of contributors who made this release possible and to prevent the release from falling too far behind master. Please be mindful of the reduced capacity of contributors to help with issues and prepare to delay upgrading if necessary.

Flipper by default​

Flipper is a developer tool for debugging mobile apps. It’s popular in the Android and iOS communities, and in this release we’ve enabled support by default for new and existing React Native apps.

Flipper provides the following features out of the box:

• Metro Actions : Reload the app and trigger the Dev Menu right from the toolbar.
• Crash Reporter : View crash reports from Android and iOS devices.
• React DevTools : Use the newest version of React DevTools right alongside all your other tools.
• Network Inspector : View all of the network requests made by device applications.
• Metro and Device Logs : View, search, and filter all logs from both Metro and the Device.
• Native Layout Inspector : View and edit the native layout output by the React Native renderer.
• Database and Preference Inspectors : View and edit the device databases and preferences.

Additionally, since Flipper is an extensible platform, it provides a marketplace that pulls plugins from NPM so you can publish and install custom plugins specific to your workflows. See the available plugins here.

For more information, check out the Flipper documentation.

New dark mode features​

We’ve added a new Appearance module to provide access to the user's appearance preferences, such as their preferred color scheme (light or dark).

const colorScheme = Appearance.getColorScheme();
if (colorScheme === 'dark') {
  // Use dark color scheme
}

We’ve also added a hook to subscribe to state updates to the users preferences:

import {Text, useColorScheme} from 'react-native';

const MyComponent = () => {
  const colorScheme = useColorScheme();
  return <Text>useColorScheme(): {colorScheme}</Text>;
};

See the docs for Appearance and useColorScheme for more information.

Moving Apple TV to react-native-tvos​

As part of our Lean Core effort and to bring Apple TV in line with other platforms like React Native Windows and React Native macOS, we’ve started to remove Apple TV specific code from core.

Going forward, Apple TV support for React Native will be maintained in react-native-community/react-native-tvos along with the corresponding react-native-tvos NPM package. This is a full fork of the main repository, with only the changes needed to support Apple TV.

Releases of react-native-tvos will be based on the public release of React Native. For this 0.62 release of react-native please upgrade Apple TV projects to use react-native-tvos 0.62.

More upgrade support​

When 0.61 was released, the community introduced a new upgrade helper tool to support developers upgrading to new versions of React Native. The upgrade helper provides a diff of changes from the version you're on to the version you're targeting, allowing you to see the changes that need to be made for your specific upgrade.

Even with this tool, issues come up when upgrading. Today we're introducing more dedicated upgrading support by announcing Upgrade-Support. Upgrade Support is a GitHub issue tracker where users can submit issues specific to upgrading their projects to receive help from the community.

We're always working to improve the upgrade experience, and we hope that these tools give users the support they need in the edge cases we haven't covered yet.

Other improvements​

• LogBox : We’re adding the new LogBox error and warning experience as an opt-in; to enable it, add require('react-native').unstable_enableLogBox() to your index.js file.
• React DevTools v4 : This change includes an upgrade to the latest React DevTools which offers significant performance gains, an improved navigation experience, and full support for React Hooks.
• Accessibility improvements : We’ve made improvements to accessibility including adding accessibilityValue, missing props on Touchables, onSlidingComplete accessibility events, and changing the default role of Switch component from "button" to "switch" .

Breaking changes​

• Remove PropTypes : We're removing propTypes from core components in order to reduce the app size impact of React Native core and to favor static type systems which check at compile time instead of runtime.
• Remove accessibilityStates : We’ve removed the deprecated accessibilityStates property in favor of the new accessibilityState prop which is a more semantically rich way for components to describe information about their state to accessibility services.
• TextInput changes : We removed onTextInput from TextInput as it’s uncommon, not W3C compliant, and difficult to implement in Fabric. We also removed the undocumented inputView prop, and selectionState .

Deprecations​

• AccessibilityInfo.fetch was already deprecated, but in this release we added a warning.
• Setting useNativeDriver is now required to support switching the default in the future.
• The ref of an Animated component is now the internal component and deprecated getNode .

Thanks​

Thank you to the hundreds of contributors that helped make 0.62 possible!

To see all the updates, take a look at the 0.62 changelog.