Jakub Piasecki
e5296cfc81
Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/47035 This PR adds support for `display: contents` style by effectively skipping nodes with `display: contents` set during layout. This required changes in the logic related to children traversal - before this PR a node would be always laid out in the context of its direct parent. After this PR that assumption is no longer true - `display: contents` allows nodes to be skipped, i.e.: ```html <div id="node1"> <div id="node2" style="display: contents;"> <div id="node3" /> </div> </div> ``` `node3` will be laid out as if it were a child of `node1`. Because of this, iterating over direct children of a node is no longer correct to achieve the correct layout. This PR introduces `LayoutableChildren::Iterator` which can traverse the subtree of a given node in a way that nodes with `display: contents` are replaced with their concrete children. A tree like this: ```mermaid flowchart TD A((A)) B((B)) C((C)) D((D)) E((E)) F((F)) G((G)) H((H)) I((I)) J((J)) A --> B A --> C B --> D B --> E C --> F D --> G F --> H G --> I H --> J style B fill:https://github.com/facebook/yoga/issues/050 style C fill:https://github.com/facebook/yoga/issues/050 style D fill:https://github.com/facebook/yoga/issues/050 style H fill:https://github.com/facebook/yoga/issues/050 style I fill:https://github.com/facebook/yoga/issues/050 ``` would be laid out as if the green nodes (ones with `display: contents`) did not exist. It also changes the logic where children were accessed by index to use the iterator instead as random access would be non-trivial to implement and it's not really necessary - the iteration was always sequential and indices were only used as boundaries. There's one place where knowledge of layoutable children is required to calculate the gap. An optimization for this is for a node to keep a counter of how many `display: contents` nodes are its children. If there are none, a short path of just returning the size of the children vector can be taken, otherwise it needs to iterate over layoutable children and count them, since the structure may be complex. One more major change this PR introduces is `cleanupContentsNodesRecursively`. Since nodes with `display: contents` would be entirely skipped during the layout pass, they would keep previous metrics, would be kept as dirty, and, in the case of nested `contents` nodes, would not be cloned, breaking `doesOwn` relation. All of this is handled in the new method which clones `contents` nodes recursively, sets empty layout, and marks them as clean and having a new layout so that it can be used on the React Native side. Relies on https://github.com/facebook/yoga/pull/1725 Changelog: [Internal] X-link: https://github.com/facebook/yoga/pull/1726 Test Plan: Added tests for `display: contents` based on existing tests for `display: none` and ensured that all the tests were passing. Reviewed By: joevilches Differential Revision: D64404340 Pulled By: NickGerleman fbshipit-source-id: f6f6e9a6fad82873f18c8a0ead58aad897df5d09
React Native
Learn once, write anywhere:
Build mobile apps with React.
Getting Started · Learn the Basics · Showcase · Contribute · Community · Support
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 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.
React Native is developed and supported by many companies and individual core contributors. Find out more in our ecosystem overview.
Contents
- Requirements
- Building your first React Native app
- Documentation
- Upgrading
- How to Contribute
- Code of Conduct
- License
📋 Requirements
React Native apps may target iOS 13.4 and Android 6.0 (API 23) 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 this discussion repo.
👏 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 bug fixes 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.