Commits on Mar 23, 2023

1. Remove 'import' from default Package Exports conditions (#955) …

   Summary:
   X-link: facebook/metro#955
   
   Pull Request resolved: #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](microsoft/TypeScript#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
   > -- microsoft/TypeScript#51669 (comment)
   
   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:
       - 681d7f8
   
   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: 1198de4e629e23f1c7a36e5d1d23d2013203d3db

   

   huntie authored and facebook-github-bot committed Mar 23, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for 7e7c2b2
   • Browse repository at this point

   Copy the full SHA

   7e7c2b2 View commit details

   Browse the repository at this point in the history