webpack/typescript/react - 错误：意外的令牌 React.Component

Question

我正在尝试使用 webpack、typescript 和 react 建立一个项目。我正在使用 babel 转换我的打字稿/反应代码。在启动开发服务器时，我得到以下错误：

Module parse failed: Unexpected token (4:6)
You may need an appropriate loader to handle this file type.
| 
| export class App extends React.Component {
>   arr = [1, 2, 3];
| 
|   render() {

Babel 不能处理数组声明？这在我看来有点奇怪。也因为我的反应类看起来不同：

app.tsx

export class App extends React.Component {

    public arr: number[] = [1, 2, 3];

    public render(): React.ReactNode {
       ...
    }
}

export default App;

我现在尝试阻止.babelrc 或babel.config.js 文件并尝试通过我的webpack.config.js 解决它：

webpack.config.js

由于澄清原因，我删除了大部分不必要的配置：

module.exports = (env) => {

    const isProduction = env.production === true;
    const isDevelopment = env.development === true;

    return {
        entry: {
            main: srcDir + '/index.tsx'
        },
        ...
        module: {
            rules: [
                {
                    oneOf: [
                       {
                        test: /\.(js|mjs|jsx|ts|tsx)$/,
                        include: srcDir,
                        loader: 'babel-loader',
                        options: {
                            babelrc: false,
                            configFile: false,
                            presets: [
                                ["@babel/preset-react"],
                                ["@babel/preset-typescript"]
                            ],
                            plugins: [
                                [
                                    'babel-plugin-named-asset-import',
                                    {
                                        loaderMap: {
                                            svg: {
                                                ReactComponent: '@svgr/webpack?-svgo,+ref![path]',
                                            },
                                        },
                                    },
                                ],
                            ],
                            cacheDirectory: true,
                            cacheCompression: isProduction,
                            compact: isProduction,
                        },
                    },
                       ...
                    ]
                }
            ]

        },
        ...
    };
};

package.json

涉及的包列表如下所示：

 ...
  "devDependencies": {
    "@babel/core": "^7.4.0",
    "@svgr/webpack": "^4.1.0",
    "babel-loader": "^8.0.5",
    "babel-plugin-named-asset-import": "^0.3.1",
    "@babel/preset-react": "^7.0.0",
    "@babel/preset-typescript": "^7.3.3",
    "webpack": "^4.29.6",
    "webpack-cli": "^3.3.0"
  },
  "dependencies": {
    "@types/react": "^16.8.12",
    "@types/react-dom": "^16.8.3",
    "@types/react-router-dom": "^4.3.1",
    "react": "^16.8.6",
    "react-dom": "^16.8.6"
  }

也许你们中的一些人有一个解决方案来解决如何通过适当的配置来防止这个问题。 :)

Answer 1

看起来它与 typescript 或 react 解析无关，我相信你缺少以下 Babel 插件：https://babeljs.io/docs/en/babel-plugin-proposal-class-properties

此插件允许 Babel 正确解析类属性，如您的数组。

安装它 npm install --save-dev @babel/plugin-proposal-class-properties

然后将其添加到插件列表中的 babel loader 配置中。

plugins: [
      "@babel/plugin-proposal-class-properties",
      [
        'babel-plugin-named-asset-import',
        {
          loaderMap: {
             svg: {
                ReactComponent: '@svgr/webpack?-svgo,+ref![path]',
             },
          },
        },
      ],
 ]