Ramanpreet Nara
0ceefb40d5
Summary: NativeModules are instantiated by the bridge. If they choose, they can capture the bridge instance that instantiated them. From within the NativeModule, the bridge can then be used to lookup other NativeModules. TurboModules have no way to do such a lookup. Both NativeModules and TurboModules need to be able to query for one another. Therefore, we have four cases: 1. NativeModule accesses NativeModule. 2. NativeModule accesses TurboModule. 3. TurboModule accesses NativeModule. 4. TurboModule accesses TurboModule. In summary, this solution extends the bridge to support querying TurboModules. It also introduces a `RCTTurboModuleLookupDelegate` protocol, which, implemented by `RCTTurboModuleManager`, supports querying TurboModules: ``` protocol RCTTurboModuleLookupDelegate <NSObject> - (id)moduleForName:(NSString *)moduleName; - (id)moduleForName:(NSString *)moduleName warnOnLookupFailure:(BOOL)warnOnLookupFailure; - (BOOL)moduleIsInitialized:(NSString *)moduleName end ``` If TurboModules want to query other TurboModules, then they need to implement this protocol and synthesize `turboModuleLookupDelegate`: ``` protocol RCTTurboModuleWithLookupCapabilities property (nonatomic, weak) id<RCTTurboModuleLookupDelegate> turboModuleLookupDelegate; end ``` NativeModules will continue to use `RCTBridge` to access other NativeModules. Nothing needs to change. When we attach the bridge to `RCTTurboModuleManager`, we also attach `RCTTurboModuleManager` to the bridge as a `RCTTurboModuleLookupDelegate`. This allows the bridge to query TurboModules, which enables our NativeModules to transparently (i.e: without any NativeModule code modification) query TurboModules. In an ideal world, all modules would be TurboModules. Until then, we're going to require that TurboModules use the bridge to query for NativeModules or TurboModules. `RCTTurboModuleManager` keeps a map of all TurboModules that we instantiated. We simply search in this map and return the TurboModule. This setup allows us to switch NativeModules to TurboModules without compromising their ability to use the bridge to search for other NativeModules (and TurboModules). When we write new TurboModules, we can have them use `RCTTurboModuleLookupDelegate` to do access other TurboModules. Eventually, after we migrate all NativeModules to TurboModules, we can migrate all old callsites to use `RCTTurboModuleLookupDelegate`. Reviewed By: fkgozali Differential Revision: D13553186 fbshipit-source-id: 4d0488eef081332c8b70782e1337eccf10717dae
React Native · 
Learn once, write anywhere: Build mobile apps with React.
See the official React Native website for an introduction to React Native.
Requirements
Supported target operating systems are >= Android 4.1 (API 16) and >= iOS 9.0. You may use Windows, macOS, or Linux as your development operating system, though building and running iOS apps is limited to macOS by default (tools like Expo can be used to get 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:
How React Native works
React Native lets you build mobile apps using JavaScript. It uses the same design as React, letting you compose a rich mobile UI from declarative components.
With React Native, you don't build a "mobile web app", an "HTML5 app", or a "hybrid app". You build a real mobile app that's indistinguishable from an app built using Objective-C, Java, Kotlin, or Swift. React Native uses the same fundamental UI building blocks as regular iOS and Android apps. You just put those building blocks together using JavaScript and React.
React Native lets you build your app faster. Instead of recompiling, you can reload your app instantly. With hot reloading, you can even run new code while retaining your application state.
React Native combines smoothly with components written in Objective-C, Java, Kotlin, or Swift. It's simple to drop down to native code if you need to optimize a few aspects of your application. It's also easy to build part of your app in React Native, and part of your app using native code directly - that's how the Facebook app works.
The focus of React Native is on developer efficiency across all the platforms you care about - learn once, write anywhere. Facebook uses React Native in multiple production apps and will continue investing in React Native. You can learn more about our open source roadmap in this blog post: Open Source Roadmap.
Full documentation
The full documentation for React Native can be found on our website. The source for the React Native documentation and website is hosted on a separate repo, https://github.com/facebook/react-native-website. Releases are discussed in the React Native Community, https://github.com/react-native-community/react-native-releases, and larger discussions and proposals are in https://github.com/react-native-community/discussions-and-proposals.
The React Native documentation only discusses the components, APIs, and topics specific to React Native (React on iOS and Android). For further documentation on the React API that is shared between React Native and React DOM, refer to the React documentation.
Join the React Native community
- Website: https://facebook.github.io/react-native
- Twitter: https://twitter.com/reactnative
- Help: https://facebook.github.io/react-native/en/help
See the CONTRIBUTING file for how to help out.
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.