更新Webpack后react-leaflet VideoOverlay.js编译遇Unexpected token错误求助

编译失败

./node_modules/react-leaflet/lib/VideoOverlay.js 10:25
Module parse failed: Unexpected token (10:25)
You may need an appropriate loader to handle this file type.
|   var overlay = new LeafletVideoOverlay(url, bounds, options);
|   if (options.play === true) {
>     overlay.getElement()?.play();
|   }
|   return createElementObject(overlay, extendContext(ctx, {

项目更新Webpack后出现上述错误，已尝试删除重装依赖、更新browserslist无效，package.json配置如下：

{
  "name": "frontend",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@types/leaflet": "^1.9.3",
    "@types/react": "^18.2.6",
    "gsap": "^3.11.5",
    "leaflet": "^1.9.4",
    "react-google-recaptcha": "^2.1.0",
    "react-leaflet": "^4.2.1",
    "react-leaflet-core": "^2.1.1",
    "react-leaflet-markercluster": "^3.0.0-rc1",
    "react-page-scroll-progress-bar": "^3.0.1",
    "react-scrollmagic-r18": "^1.0.3",
    "video-react": "^0.16.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": [
    ">0.2%",
    "not dead",
    "not op_mini all"
  ],
  "devDependencies": {
    "webpack": "^4.28.3"
  }
}

问题根源 #

错误中的?.是ES2020的可选链操作符，你的Webpack 4环境未配置转译第三方依赖（react-leaflet）的babel规则——默认react-scripts不会处理node_modules里的代码，导致新语法无法被解析。

可行解决方案 #

方案1：用react-app-rewired扩展babel配置 #

• 安装依赖：

  npm install --save-dev react-app-rewired customize-cra @babel/plugin-proposal-optional-chaining @babel/plugin-proposal-nullish-coalescing-operator
  

• 项目根目录新建config-overrides.js：

  const { override, addBabelPlugins, addExternalBabelPlugins } = require('customize-cra');
  
  module.exports = override(
    // 给项目代码添加语法支持插件
    addBabelPlugins(
      '@babel/plugin-proposal-optional-chaining',
      '@babel/plugin-proposal-nullish-coalescing-operator'
    ),
    // 给第三方依赖添加插件，转译react-leaflet代码
    addExternalBabelPlugins(
      '@babel/plugin-proposal-optional-chaining',
      '@babel/plugin-proposal-nullish-coalescing-operator'
    )
  );
  

• 修改package.json的scripts：

  "scripts": {
    "start": "react-app-rewired start",
    "build": "react-app-rewired build",
    "test": "react-app-rewired test",
    "eject": "react-scripts eject"
  }
  

方案2：降级react-leaflet到兼容版本 #

react-leaflet 3.x版本未使用可选链语法，可直接降级适配现有环境：

npm install react-leaflet@3.2.5 react-leaflet-core@1.1.0

方案3：升级Webpack 5（适配react-scripts） #

react-scripts 5.x自带Webpack 5，默认支持ES2020语法，无需额外配置：

1. 卸载手动安装的Webpack（避免和react-scripts自带版本冲突）：

   npm uninstall webpack
   

2. 升级react-scripts：

   npm install react-scripts@latest
   

通用收尾操作 #

完成上述任一方案后，执行以下步骤确保依赖环境干净：

rm -rf node_modules package-lock.json
npm install

内容的提问来源于stack exchange，提问作者D333