Happy new year everyone! Today we are announcing the latest release of React Native, 0.67.0, along with some updates on the release process that we have been working on in the past few months.
Since we announced Hermes in 2019, it has been increasingly gaining adoption in the community. The team at Expo, who maintain a popular meta-framework for React Native apps, recently announced experimental support for Hermes after being one of the most requested features of Expo. The team at Realm, a popular mobile database, also recently shipped its alpha support for Hermes. In this post, we want to highlight some of the most exciting progress we've made over the past two years to push Hermes towards being the best JavaScript engine for React Native. Looking forward, we are confident that with these improvements and more to come, we can make Hermes the default JavaScript engine for React Native across all platforms.
Today we’re releasing React Native v0.66 for Android 12 and iOS 15 support alongside fixes and general updates.
React Native has been very successful at raising the bar for mobile development, both at Facebook and elsewhere in the industry. As we interact with computers in new ways and as new devices are invented, we want React Native to be there for everyone. Although React Native was originally created to build mobile apps, we believe that focusing on many platforms and building to each platform’s strengths and constraints has a symbiotic effect. We have seen huge benefits when we extended this technology to desktop and virtual reality, and we're excited to share what this means for the future of React Native.
Over the past year so much has changed in our world, React Native being no exception. We've welcomed new members to our team (whom we are excited to eventually meet in person!), our projects have matured and new opportunities have arisen. We're excited to share all this with you in this post and others to come!
At Facebook, our team works in half-year cycles. Each half we review our strategy, set plans, and share them internally. Today, we want to share our H2 plans with you, our community.
H2 2021 is an exciting half for React Native. Our areas of focus include nurturing the community, beginning to roll out the new architecture to open source, and pushing the technology forward.
Today we’re releasing React Native version 0.65 with a new version of Hermes, improvements to accessibility, package upgrades, and more.
Hermes, Facebook’s open source JavaScript VM optimized for React Native, has been upgraded to version 0.8.1. Some of the stand-out features in this release are:
Intl) is now built into Hermes on Android and enabled by default, with only 57-62K per API size overhead (compared to JSC's 6MiB). With this change, Hermes users no longer require locale polyfills. A big thank you to @mganandraj and other partners at Microsoft for driving the implementation to make this happen!Function.prototype.toString that fixed a performance drop due to improper feature detection and supports the source code injecting use case.You can find the full Hermes changelog here.
Follow steps here to opt-in your app to Hermes if you haven’t already to leverage these new features and gains!
Last year Facebook took the GAAD pledge to improve accessibility within React Native. 0.65 shares the results of this pledge and other accessibility wins! Some notable changes include:
getRecommendedTimeoutMillis API on Android. This exposes a user’s preferred default timeout value as set in Android’s accessibility options and is for users who may need extra time to review or reach controls, etc.disabled and unselected on components.You can follow along or contribute to our outstanding accessibility issues here!
react-native-codegen version 0.0.7 is now needed as a devDependency in the package.json.This release includes over 1100 commits from 61 contributors. Thank you to everyone who has contributed and supported this release! You can find the full changelog here.
It has been one year since Facebook took the GAAD Pledge to make React Native accessible and the project has exceeded our expectations. We are excited to announce that this project will continue throughout 2021 and want to update everyone on our progress so far. Following a thorough analysis of the accessibility gaps in React Native last year, work began on filling these gaps.
We started with 90 outstanding gap analysis issues and from March 2021, when the project launched on GitHub, until now:
11 issues have been closed by the community.
19 issues were evaluated and closed by the React Native team.
9 pull requests were merged.
1 pull request was merged into the React Native docs.
We want to recognize and thank the React Native community for the significant progress towards a more accessible React Native over the past year. Every contributor's effort has counted in making progress on improving React Native Accessibility.
It has been four weeks since we reached out to the GitHub community with a thoroughly reviewed gap analysis and list of issues to improve React Native's accessibility. With the help of the React Native community, we are already making great progress on improving accessibility. Community members have been helping contributors, reviewing tests, and bringing attention to prior accessibility issues. Since March 8th the community has closed six issues with four pull requests and seven other pull requests are in the pipeline for review.
While this work continues, the React Native and Accessibility teams at Facebook are evaluating accessibility bugs and issues that were submitted prior to this initiative, to determine if they are already covered by our current gap analysis or if there are additional issues that need to be brought into the project. One new issue has already been discovered and moved into the project, four others directly mapped to existing issues and two others are expected to be closed by addressing existing issues that address the root cause of their issue.
Thank you to all the community members who have participated. You are truly moving the needle in making React Native more accessible for everyone!
Today we’re releasing React Native 0.64 that ships with support for Hermes 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 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.
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.
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 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.
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.
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.
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.