Today we’re releasing 0.72!
This release adds highly requested features for Metro, better error handling, and other developer experience improvements. So much of this work was prioritized from your feedback on the 2022 community survey -- thank you to all those that participated!
Today we’re releasing React Native version 0.71! This is a feature-packed release including:
In this post we’ll cover some of the highlights of 0.71.
We are excited to release a new version of React Native, 0.70.0. This version comes with several improvements like a new unified configuration for Codegen, Hermes as default engine, and full CMake support for Android builds along with a refresh of the documentation for the New Architecture. Read on to learn more!
Last October, we announced that we had started work towards making Hermes the default engine for all React Native apps.
Hermes has provided a lot of value to React Native inside of Meta, and we believe the open-source community will benefit as well. Hermes is designed for resource constrained devices and optimizes for start up, app size, and memory consumption. One key difference between Hermes and other JS engines is its ability to compile JavaScript source code to bytecode ahead of time. This precompiled bytecode is bundled inside the binary, and saves the interpreter from having to perform this expensive step during app startup.
Since the announcement, a lot of work has gone into making Hermes better, and today, we are excited to share that React Native 0.70 will ship with Hermes as the default engine. This means that all new projects starting on v0.70 will have Hermes enabled by default. With the rollout coming up in July, we want to work closely with the community and make sure the transition is smooth and brings value to all users. This blogpost will go over what you can expect from the change, performance benchmarks, new features, and more. Note that you don’t need to wait for React Native 0.70 to start using Hermes - you can follow these instructions to enable Hermes on your existing React Native app.
Note that while Hermes will be enabled by default in new React Native projects, support for other engines will continue.
We are excited to release a new version of React Native, 0.69.0. This version comes with several improvements for the New Architecture of React Native and new features: React 18 support & bundled Hermes. Read on to learn more!
Hello everyone! Today we are announcing the 0.68.0 release of React Native, with opt-in to the New React Native Architecture, bug fixes and more.
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.
Today we’re releasing React Native v0.66 for Android 12 and iOS 15 support alongside fixes and general updates.
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.
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.