react/create-react-app

[v4] Bug: React 17, React is not defined after ejecting

Open

#9,953 创建于 2020年10月29日

在 GitHub 查看
 (20 评论) (4 反应) (0 负责人)JavaScript (103,386 star) (27,059 fork)batch import
contributions: up for grabs!good first issueissue: bugissue: needs investigation

描述

React version: 17.0.1

Steps To Reproduce

  1. npx create-react-app my-app
  2. cd my-app
  3. npm start (Works like a charm)
  4. npm run eject
  5. npm i
  6. npm start (ReferenceError: React is not defined)

Link to code example: https://codesandbox.io/s/ecstatic-wood-ou6px

The current behavior

I upgraded react to 17 and removed "import React"s from my project files (except index.js where react mounted). But I got "ReferenceError: React is not defined" in those files. To investigate the issue behind this, I created a new react app, the new JSX transformation was working. But when I eject, it throws the same errors. So; Without react-scripts, new JSX transformation doesn't working.

The expected behavior

Components should render without declaring React (import React from "react") if React is in scope.

贡献者指南

技术栈
javascriptreact
领域
frontend
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
half day
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
active
清晰度议题是否清楚说明期望改动、验收标准和下一步。
mostly clear
前置要求
basic React knowledgeunderstanding of create react app
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
60
研究方向
Investigate the webpack configuration after ejecting. The new JSX transform requires specific Babel presets (like @babel/preset react with runtime: 'automatic'). Compare the ejected config's Babel settings with the non ejected react scripts setup. Look for missing or misconfigured Babel plugins in the ejected config files (e.g., webpack.config.js, babel.config.js). The linked CodeSandbox may provide hints.