React.js 当前未启用对实验性语法 'classProperties' 的支持错误

Question

当我尝试将 react-native-vector-icon 与使用 react-native-web 构建的 React 项目一起使用时，我得到

Support for the experimental syntax 'classProperties' isn't currently enabled

我尝试了以下解决方案，但 none 对我有用。

Support for the experimental syntax 'classProperties' isn't currently enabled
"loose": true is not fixing Support for the experimental syntax 'classProperties' isn't currently enabled

我的package.json

{
  "name": "react-webiste",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "axios": "^0.19.2",
    "fsevents": "^2.1.2",
    "react": "^16.8.6",
    "react-dom": "^16.8.6",
    "react-native": "^0.62.1",
    "react-native-svg": "^12.1.0",
    "react-native-vector-icons": "^6.6.0",
    "react-native-web": "^0.12.2",
    "react-router-dom": "^5.1.2",
    "react-scripts": "3.0.0",
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "@babel/plugin-proposal-class-properties": "^7.8.3"
  }
}

babel.config.js

module.exports = {
  presets: ["@babel/preset-env", "@babel/preset-react"],
  plugins: ["@babel/plugin-proposal-class-properties",{"loose": true}]
};

任何人都可以建议我应该如何解决这个问题。

Answer 1

编辑：您的问题似乎是图书馆所有者当前遇到的问题。该库是为 react-native 构建的，用户习惯于手动转译。你可以找到 the GitHub project issue here

但是，正如某些用户所建议的那样，您可以尝试使用 config-overrides.js，将 resolveApp('../node_modules/react-native-vector-icons') 添加到您的捆绑步骤中，例如 described in this GitHub comment。

为了使用 config-overrides，您应该迁移到 react-app-rewired(https://github.com/timarney/react-app-rewired).

我将粘贴配置覆盖更改以供将来参考，感谢 jookovjok，他已经满了 config-overrides.js:

const appIncludes = [
    ...
    resolveApp('../node_modules/react-native-vector-icons') // <- HERE
    ]
... 
    config.module.rules[2].oneOf[1].options.plugins = [
        ...
        require.resolve('@babel/plugin-proposal-class-properties') // <- HERE
    ]...

编辑前的旧答案：

您是否正确粘贴了 babel.config.js？在我看来，您的 plugins 声明拼错了：

将插件行更改为：（删除多余的 t）：

plugins: ["@babel/plugin-proposal-class-properties", {"loose": true}]

Answer 2

在一般情况下，所有 babel 配置都可以从 babel.config.js 或任何其他受支持的 formate 文件传递下来。但就我而言，webpack.config.js 中的 babel-loader 有自己的选项，因此所有配置都被覆盖为 described by Babel team on Github Comment.

其次，我使用 metro-react-native-babel-preset 而不是 @babel/plugin-proposal-class-properties 来解决 babel 丢失的问题。

这是我的 Webpack Config 弹出应用程序后：

   {
       test: /\.(js|mjs)$/,
       exclude: /@babel(?:\/|\{1,2})runtime/,
       loader: require.resolve('babel-loader'),
       options: {
           babelrc: false,
           configFile: false,
           compact: false,

          // Added the module here
           presets: [
             [
                require.resolve('babel-preset-react-app/dependencies'),
                { helpers: true },
             ],["module:metro-react-native-babel-preset"]
          ],

      // More configuration codes goes here 


 {
         test: /\.(js|mjs|jsx|ts|tsx)$/,
         enforce: 'pre',
         use: [
           {
             options: {
               cache: true,
               formatter: require.resolve('react-dev-utils/eslintFormatter'),
               eslintPath: require.resolve('eslint'),
               resolvePluginsRelativeTo: __dirname,

             },
             loader: require.resolve('eslint-loader'),
           },
         ],
         include:[  //Change here as well
           paths.appSrc,
           path.resolve('node_modules/react-native-vector-icons'),
         ]
       },

完成所有这些后，react-native-vector-icon 将呈现但不会加载任何内容。为此，我们需要将以下样式添加到 App.css 或任何根样式 sheet.


/*Import the Icon CSS*/
@font-face {
  font-family: "Entypo";
  src: url("~react-native-vector-icons/Fonts/Entypo.ttf") format("truetype");
}

@font-face {
  font-family: "EvilIcons";
  src: url("~react-native-vector-icons/Fonts/EvilIcons.ttf") format("truetype");
}

@font-face {
  font-family: "FontAwesome";
  src: url("~react-native-vector-icons/Fonts/FontAwesome.ttf")
  format("truetype");
}

@font-face {
  font-family: "fontcustom";
  src: url("~react-native-vector-icons/Fonts/Foundation.ttf") format("truetype");
}

@font-face {
  font-family: "Ionicons";
  src: url("~react-native-vector-icons/Fonts/Ionicons.ttf") format("truetype");
}

@font-face {
  /*font-family: 'MaterialCommunityIcons';*/
  font-family: "Material Design Icons";
  src: url("~react-native-vector-icons/Fonts/MaterialCommunityIcons.ttf")
  format("truetype");
}

@font-face {
  font-family: "MaterialIcons";
  src: url("~react-native-vector-icons/Fonts/MaterialIcons.ttf")
  format("truetype");
}

@font-face {
  font-family: "Octicons";
  src: url("~react-native-vector-icons/Fonts/Octicons.ttf") format("truetype");
}

@font-face {
  font-family: "simple-line-icons";
  src: url("~react-native-vector-icons/Fonts/SimpleLineIcons.ttf")
  format("truetype");
}

@font-face {
  font-family: "Zocial";
  src: url("~react-native-vector-icons/Fonts/Zocial.ttf") format("truetype");
}

Answer 3

我在几天内尝试了很多东西。让 classProperties 在 react-native-web 上工作的最终解决方案是遵循这个非常受欢迎的 repo 的简单指南：https://reactnativeelements.com/docs/web_usage/

您必须在文件 config-overrides.js:

中添加导致问题的包 (react-native-vector-icons)

const path = require('path');
const { override, addBabelPlugins, babelInclude } = require('customize-cra');

module.exports = override(
  ...addBabelPlugins('@babel/plugin-proposal-class-properties'),
  babelInclude([
    path.resolve(__dirname, 'node_modules/react-native-elements'),
    path.resolve(__dirname, 'node_modules/react-native-vector-icons'),
    path.resolve(__dirname, 'node_modules/react-native-ratings'),
    path.resolve(__dirname, 'src'),
  ])
);

React.js 当前未启用对实验性语法 'classProperties' 的支持错误

Support for the experimental syntax 'classProperties' isn't currently enabled error on a React.js

javascript

reactjs

babeljs

react-native

react-native-web