ReferenceError: React没有定义，即使我已经安装了依赖项

Question

当我使用'EmailJS'添加联系人表单时出现错误。我可以看到Package上的依赖项。Json看起来很好，但是它说没有定义。

"react": "^17.0.2",
"react-dom": "^17.0.2",

我按照建议更改了导入格式，

import React from 'react';
import ReactDOM from 'react-dom';

也重新安装了，但是，错误仍然没有修复。

ReferenceError: React is not defined
at Object.children (C:UsersHanDesktopandamilo24-shopifystorehelp.nextserverpagesindex.js:3460:62)
at BaseAccordion.render (C:UsersHanDesktopandamilo24-shopifystorehelp.nextserverpagesindex.js:3595:23)
at processChild (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesreact-domcjsreact-dom-server.node.development.js:3450:18)
at resolve (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesreact-domcjsreact-dom-server.node.development.js:3270:5)
at ReactDOMServerRenderer.render (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesreact-domcjsreact-dom-server.node.development.js:3753:22)
at ReactDOMServerRenderer.read (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesreact-domcjsreact-dom-server.node.development.js:3690:29)
at renderToString (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesreact-domcjsreact-dom-server.node.development.js:4298:27)
at Object.renderPage (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesnextdistnext-serverserverrender.js:54:854)
at Function.getInitialProps (C:UsersHanDesktopandamilo24-shopifystorehelp.nextserverpages_document.js:791:19)
at Function.getInitialProps (C:UsersHanDesktopandamilo24-shopifystorehelp.nextserverpages_document.js:1373:85)
at loadGetInitialProps (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesnextdistnext-serverlibutils.js:5:101)
at renderToHTML (C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesnextdistnext-serverserverrender.js:54:1145)
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
at async C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesnextdistnext-serverservernext-server.js:112:97
at async C:UsersHanDesktopandamilo24-shopifystorehelpnode_modulesnextdistnext-serverservernext-server.js:105:142

谁能告诉我这里缺少什么?

Answer 1

首先检查你是否使用Babel和react 17。添加"runtime":";automatic"到配置

{
"presets": ["@babel/preset-env", ["@babel/preset-react", {
"runtime": "automatic"
}]]

}

如果没有，检查添加联系人表单时实际更改的文件。主要在babel或webpack等配置文件中。

如果使用webpack，在webpack.config.json中得到这样的配置

externals: {
'react': 'React'
},

删除它

如果所有这些都失败了，记住react没有被捆绑，相反可能会调用window.react，所以只需添加

import React from 'react';
import ReactDOM from 'react-dom';
window.React = React