Rubén Norte
47e490f084
Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/48427 Changelog: [internal] The `ReactNativeElement` class was refactored for performance reasons, and the current implementation does **NOT** call `super()`, and it inlines the parent constructor instead. When it eventually extends `EventTarget`, things won't work as expected because the existing `EventTarget` implementation has constructor dependencies. This refactors the current implementation of `EventTarget` to eliminate those constructor side-effects, and eliminates the constructor altogether. This breaks encapsulation, but it has some positive side-effects on performance: 1. Creating `EventTarget` instances is faster because it has no constructor logic. 2. Improves memory by not creating maps to hold the event listeners if no event listeners are ever added to the target (which is very common). 3. Improves the overall runtime performance of the methods in the class by migrating away from private methods (which are known to be slow on the babel transpiled version we're currently using). Extra: it also simplifies making window/the global scope implement the EventTarget interface :) ## Benchmark results Before: | Latency average (ns) | Latency median (ns) | Samples | Task name | Throughput average (ops/s) | Throughput median (ops/s) | | ---|--- |--- |--- |---|---| | 8234.22 ± 0.27% | 8132.00 | 121445 | dispatchEvent, no bubbling, no listeners | 122323 ± 0.02% | 122971 | | 9001.22 ± 0.41% | 8883.00 | 111097 | dispatchEvent, no bubbling, single listener | 111981 ± 0.02% | 112575 | | 51777.94 ± 0.58% | 51247.00 | 19314 | dispatchEvent, no bubbling, multiple listeners | 19393 ± 0.04% | 19513 | | 8256.65 ± 0.29% | 8152.00 | 121115 | dispatchEvent, bubbling, no listeners | 122031 ± 0.02% | 122669 | | 9064.32 ± 0.44% | 8933.00 | 110323 | dispatchEvent, bubbling, single listener per target | 111265 ± 0.02% | 111944 | | 51879.66 ± 0.27% | 51447.00 | 19276 | dispatchEvent, bubbling, multiple listeners per target | 19325 ± 0.04% | 19437 | After: | Latency average (ns) | Latency median (ns) | Samples | Task name | Throughput average (ops/s) | Throughput median (ops/s)| | ---------------------|---------------------|---------|--------------------------------------------------------|----------------------------|--------------------------| | 5664.62 ± 0.50% | 5588.00 | 176535 | dispatchEvent, no bubbling, no listeners | 178219 ± 0.02% | 178955 | | 7232.86 ± 0.50% | 7131.00 | 138258 | dispatchEvent, no bubbling, single listener | 139540 ± 0.02% | 140233 | | 50957.51 ± 0.71% | 50336.00 | 19625 | dispatchEvent, no bubbling, multiple listeners | 19751 ± 0.04% | 19866 | | 5692.36 ± 0.50% | 5618.00 | 175675 | dispatchEvent, bubbling, no listeners | 177315 ± 0.02% | 177999 | | 7277.82 ± 0.38% | 7181.00 | 137404 | dispatchEvent, bubbling, single listener per target | 138560 ± 0.02% | 139256 | | 50493.64 ± 0.28% | 50105.00 | 19805 | dispatchEvent, bubbling, multiple listeners per target | 19855 ± 0.04% | 19958 | Reviewed By: yungsters Differential Revision: D67758408 fbshipit-source-id: f8da1788251c9e21377de5ab730875bcc7610361
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 15.1 and Android 7.0 (API 24) 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 repository, @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.