Alex HuntandFacebook GitHub Bot 308838c0ff Remove 'import' from default Package Exports conditions (#955)
Summary:
X-link: https://github.com/facebook/metro/pull/955

Pull Request resolved: https://github.com/facebook/react-native/pull/36584

Changelog:
[General][Changed] - Default condition set for experimental Package Exports is now `['require', 'react-native']`

The [Exports RFC](https://github.com/react-native-community/discussions-and-proposals/blob/main/proposals/0534-metro-package-exports-support.md) had assumed that supporting the `"import"` condition was a syntax-only difference, given we are not in a Node.js environment — and so was worthwhile to support for maximal ecosystem compatibility.

{F915841105}

This assumption is similar to [`--moduleResolution bundler` in TypeScript 5.0](https://github.com/microsoft/TypeScript/pull/51669):

> bundlers and runtimes that include a range of Node-like resolution features and ESM syntax, but do not enforce the strict resolution rules that accompany ES modules in Node or in the browser
> -- https://github.com/microsoft/TypeScript/pull/51669#issue-1467004047

However, robhogan has rightly pointed out that **we should not do this!**

- ESM (once transpiled) is **not** simply a stricter subset of in-scope features supported by CJS. For example, it supports top-level async, which would be breaking at runtime.
- We recently made the same change for our Jest environment:
    - https://github.com/facebook/react-native/commit/681d7f8113d2b5e9d6966255ee6c72b50a7d488a

As such, we are erring on the side of correctness and supporting only `['require', 'react-native']` in our defaults. At runtime, all code run by React Native is anticipated to be CommonJS. `"exports"` will instead allow React Native to correctly select the CommonJS versions of modules from all npm packages.

Metro changelog: [Experimental] Package Exports `unstable_conditionNames` now defaults to `['require']`

Reviewed By: robhogan

Differential Revision: D44303559

fbshipit-source-id: 0077e547e7775e53d1e4e9c3a9d01347f4fb7d4a
2023-03-23 06:06:42 -07:00
2019-09-19 18:36:25 -07:00
2023-02-27 13:47:09 -08:00
2023-03-17 15:46:25 -07:00
2023-03-17 15:46:25 -07:00
2023-03-09 01:27:43 -08:00
2023-02-27 13:47:09 -08:00
2023-02-27 13:47:09 -08:00

React Native

Learn once, write anywhere:
Build mobile apps with React.

React Native is released under the MIT license. Current CircleCI build status. Current npm package version. PRs welcome! Follow @reactnative

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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

React Native apps may target iOS 12.4 and Android 5.0 (API 21) 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.

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