Ramanpreet Nara
58cd20459f
Summary: In D14571128, we made it so that when a JS object's property was `undefined`, we wouldn't insert that property into the corresponding NSDictionary. Here are two important observations about that diff: 1. ALL JS `null`s were now being converted to `NSNull`, and JS `undefined`s were now being converted to `nil`. 2. If a JS object's property was explicitly `null`, then we'd insert `NSNull` into the corresponding dictionary. Considering that when a property doesn't exist in a `NSDictionary`, property access returns `nil`, I've made it so that if a JS object's property is either `null` or `undefined`, then we simply do not insert it in the corresponding `NSDictionary`. Also, I've reverted #1 and made it so that `undefined` and `null` always map to the ObjC `nil`. This shouldn't unfix the problem that D14571128 was trying to fix. Here's my understanding of the problem that D14571128 was trying to fix (to make sure I'm not breaking something by this diff). This method was invoked from JS. ``` RCT_EXPORT_METHOD(logEvents:(NSDictionary *)events) { RCTAssert(events, @"You should provide events for logger"); [[NSNotificationCenter defaultCenter] postNotificationName:@"FBReactPerfLoggerDidReceiveEventsNotification" object:nil userInfo:@{@"FBReactPerfLoggerUserInfoPerfEventsKey" : [events copy]}]; } ``` The above dispatch calls into this method, which appends `events` into `_pendingJSPerfEvents`. ``` - (void)reactPerfLoggerDidReceiveEvents:(NSNotification *)notification { NSDictionary *events = notification.userInfo[@"FBReactPerfLoggerUserInfoPerfEventsKey"]; if (events) { dispatch_async(_eventQueue, ^{ if (self->_sessionData.perfLoggerFlagId != nil) { if ([self processJSPerfEvents:events]) { [self reportMetricsIfFinished]; } } else { [self->_pendingJSPerfEvents addObject:events]; } }); } } ``` Then, in `_processJSPerfEvents`, we do the following (link: https://fburl.com/tr4wr2a7): ``` NSNumber *actionId = events[@"actionId"]; if (actionId) { self->_sessionData.actionId = actionId; } ``` So, if `undefined` or `null` was passed in as the `actionId` property of the `events` JS object in `FBReactPerformanceLogger logEvents:`, then we'd default the `NSDictionary` to have `NSNull` in the corresponding property. This is bad because we had this line in FBReactWildePerfLogger (link: https://fburl.com/2nsywl2n): `actionId ? [actionId shortValue] : PerfLoggerActions.SUCCESS`. Essentially, this is the same problem that my diff is trying to fix. Reviewed By: fkgozali Differential Revision: D14625287 fbshipit-source-id: c701d4b6172484cee62494256175e8b205b23c73
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 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.