d6d381180b
Summary: After the change, YogaLayoutableShadowNode will preserve dirty flag (being false) in cases where: * a node was cloned with same children; * changes in props don't affect layout. Motivation: In Fabric we always were aggressive about dirting yoga nodes: when we clone the node, we always dirty underlying Yoga node. I think that was the case because we don't deeply understand how the system works and we always had more severe problems to fix. Now, we faced an issue that forces us to think about that problem carefully (more about that later). (I don't expect that will improve TTI performance, but that's possible if we do a lot of changes in the hierarchy during initial load process.) I see two main use cases where we have to be smart about dirtied yoga nodes: Case 1. Native local commits which do *not* modify yoga styles.E.g. in a case where ScrollView updates the internal state (which has offset info) really really frequently. (It will be implemented later.) That `contentOffset` info does not or might not affect layout, so we should not pay for this. Case 2. Legit React commits which do *not* modify yoga styles. E.g. in a case where only the background color of some view changes, we don't need to relayout anything. Unfortunately, we do this in Fabric because of two major reasons: * We don't make a difference between any changes in Props. * React constructs new children of cloned node iteratively, calling `appendChild`. That makes implementing optimization really challenging because we don't know when the process ends. And when it ends we have very few pieces of information about how the state looked before. This diff stack will handle the problems of the first kind. The main motivation is: we want to have state updates to be as lean as possible. Reviewed By: JoshuaGross Differential Revision: D14472752 fbshipit-source-id: 68374f60cb07de9ab65bf1f6d94c828985359fa5
React Native
Learn once, write anywhere:
Build mobile apps with React.
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React Native brings React's declarative UI framework to iOS and Android. With React Native, you use native UI controls and have full access to the native platform.
- Declarative. React makes it painless to create interactive UIs. Declarative views make your code more predictable and easier to debug.
- Component-Based. Build encapsulated components that manage their own state, then compose them to make complex UIs.
- Developer Velocity. See local changes in seconds. Changes to JavaScript code can be live reloaded without rebuilding the native app.
- Portability. Reuse code across iOS, Android, and other platforms.
Contents
- Requirements
- Building your first React Native app
- Documentation
- Upgrading
- How to Contribute
- Code of Conduct
- License
📋 Requirements
React Native apps may target iOS 9.0 and Android 4.1 (API 16) or newer. You may use Windows, macOS, or Linux as your development operating system, though building and running iOS apps is limited to macOS. Tools like Expo can be used to work around this.
🎉 Building your first React Native app
Follow the Getting Started guide. The recommended way to install React Native depends on your project. Here you can find short guides for the most common scenarios:
📖 Documentation
The full documentation for React Native can be found on our website.
The React Native documentation discusses components, APIs, and topics that are specific to React Native. For further documentation on the React API that is shared between React Native and React DOM, refer to the React documentation.
The source for the React Native documentation and website is hosted on a separate repo, @facebook/react-native-website.
🚀 Upgrading
Upgrading to new versions of React Native may give you access to more APIs, views, developer tools and other goodies. See the Upgrading Guide for instructions.
React Native releases are discussed in the React Native Community, @react-native-community/react-native-releases.
👏 How to Contribute
The main purpose of this repository is to continue evolving React Native core. We want to make contributing to this project as easy and transparent as possible, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving React Native.
Code of Conduct
Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read the full text so that you can understand what actions will and will not be tolerated.
Contributing Guide
Read our Contributing Guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React Native.
Open Source Roadmap
You can learn more about our vision for React Native in the Roadmap.
Good First Issues
We have a list of good first issues that contain bugs which have a relatively limited scope. This is a great place to get started, gain experience, and get familiar with our contribution process.
Discussions
Larger discussions and proposals are discussed in @react-native-community/discussions-and-proposals.
📄 License
React Native is MIT licensed, as found in the LICENSE file.
React Native documentation is Creative Commons licensed, as found in the LICENSE-docs file.