Mike GrabowskiandFacebook GitHub Bot
a8e85026cf
Summary: Historically, React Native didn't support a lot of custom project structures apart from the standard flat directory with `ios` and `android` folders. The CLI had to be explicitly started from the project root, otherwise Metro didn't work right. In order to resolve the project root in the most accurate way, React Native assumed that project root is always `../../` from its location in `node_modules` - this is not true when the installation gets hoisted (e.g. in a monorepo). To address that, janicduplessis brought support for custom [`PROJECT_ROOT`](https://github.com/facebook/react-native/commit/9ccde378b6e6379df61f9d968be6346ca6be7ead) that allowed overriding the `../../` in case it wasn't true. Today, CLI is able to automatically resolve the project root, no matter where it's started. It will traverse the tree of the directories upwards and stop as soon as it meets `package.json`. As a result, it doesn't really matter from where we start the CLI anymore as a part of `react-native-xcode.sh`. By replacing the default value of `$REACT_NATIVE_DIR/../../` with `$PWD, that is default for all Xcode scripts, we can make the setup for monorepo easier - nobody will need to set `$PROJECT_ROOT` in order to override the incorrect defaults. By default, all scripts defined in Xcode run from `$PWD` directory, which is the location of the iOS project. In the future, we will be able to remove `cd` entirely. To better understand this PR, let's look a few hypothetical structures as an example: #### Monorepo: > tl;dr works out of the box, no need to mess around with paths ``` - package.json - packages/ - my-app/ - index.js - package.json - ios/ - MyApp.xcodeproj ``` **Before this PR**, the `react-native-xcode.sh` will start the CLI like this: ```bash cd $REACT_NATIVE_DIR/../../ node <absolute_path_to_cli.js> bundle --entry-point index.js ``` - Because we change the directory to the root of monorepo, CLI throws an error. All in all, there's no `react-native` dependency at the workspace root. - Some users turn `no hoist` in an act of troubleshooting the errors, which resolves the problem - `react-native` is moved under `my-app/node_modules` which makes this mechanism resolve properly. - Some users find out about `PROJECT_ROOT` and set it to overwrite the default value. For example, setting `export PROJECT_ROOT = "$PWD/../` will set the directory to `my-app`, which has a dependency on `react-native` in a `package.json` and makes the CLI happy. **After this PR**, the `react-native-xcode.sh` will start the CLI like this: ```bash cd $PWD node <absolute_path_to_cli.js> bundle --entry-point index.js ``` - The `$PWD` is `packages/my-app/ios/` because that's where the Xcode project is located. CLI will automatically set the root to `../` because that's where it finds `package.json` with `react-native` dependency. It will pass that root to Metro, unless users have set a different one themselves. Thanks to that, all paths to JavaScript files remain working and unaffected. - No need to set `PROJECT_ROOT` anymore. - We don't rely on the location of `node_modules`, which is cleaner and future proof. #### Standard: > tl;dr no changes ``` - ios/ - MyApp.xcodeproj - index.js - package.json ``` **Before this PR**, the `react-native-xcode.sh` will start the CLI like this: ```bash cd $REACT_NATIVE_DIR/../../ node <absolute_path_to_cli.js> bundle --entry-point index.js ``` - Everything works fine. Path from `react-native` inside `node_modules` is correct - the project root is set right to `/` **After this PR**, the `react-native-xcode.sh` will start the CLI like this: ```bash cd $PWD node <absolute_path_to_cli.js> bundle --entry-point index.js ``` - The root will be set to where Xcode project is located, which is `/ios`. This is the PWD for all Xcode scripts. CLI will look for the `package.json` going upwards from `ios` folder. Will stop at `/`, find out it has `react-native` dependency, load it and its commands and proceed further. ## Changelog [iOS] [Feature] - Better monorepo support when building release apk Pull Request resolved: https://github.com/facebook/react-native/pull/28354 Test Plan: - All projects (standard/monorepo) run without issues. - PROJECT_ROOT is not needed. CC: Titozzz (who wrote monorepo guide), alloy, bartolkaruza Reviewed By: cpojer Differential Revision: D20558005 Pulled By: hramos fbshipit-source-id: 2551120beadcfd4c2f1393ce8a2c2fa6b93c9290
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 10.0 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 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.