React Native中导入Expo模块失败的问题求助

我看到你在执行import Expo from 'expo'时遇到了模块解析失败的打包错误，这个问题和React Native的Haste模块映射机制相关，下面是经过验证的解决步骤，你可以按顺序尝试：

解决步骤 #

• 清除watchman的所有监听：

  watchman watch-del-all
  

• 删除node_modules文件夹并重新安装所有依赖：

  rm -rf node_modules && npm install
  

• 重置Metro Bundler缓存，两种方式任选其一即可：

  rm -rf /tmp/metro-bundler-cache-*
  

  或者

  npm start -- --reset-cache
  

• 删除Haste模块映射缓存：

  rm -rf /tmp/haste-map-react-native-packager-*
  

另外，从你的项目依赖配置来看，当前package.json里并没有添加expo依赖，这可能也是问题的核心根源之一！ 你需要先执行以下命令安装Expo模块：

npm install expo

报错详情 #

error: bundling failed: Error: Unable to resolve module expo from C:\Users\reactnative\navigate\App.js: Module expo does not exist in the Haste module map.

报错堆栈信息 #

at ModuleResolver.resolveDependency (C:\Users\reactnative\navigate\node_modules\metro\src\node-haste\DependencyGraph\ModuleResolution.js:183:15)
at ResolutionRequest.resolveDependency (C:\Users\reactnative\navigate\node_modules\metro\src\node-haste\DependencyGraph\ResolutionRequest.js:52:18)
at DependencyGraph.resolveDependency (C:\Users\reactnative\navigate\node_modules\metro\src\node-haste\DependencyGraph.js:273:16)
at Object.resolve (C:\Users\reactnative\navigate\node_modules\metro\src\lib\transformHelpers.js:261:42)
at dependencies.map.result (C:\Users\reactnative\navigate\node_modules\metro\src\DeltaBundler\traverseDependencies.js:391:31)
at Array.map (<anonymous>)
at resolveDependencies (C:\Users\reactnative\navigate\node_modules\metro\src\DeltaBundler\traverseDependencies.js:388:18)
at C:\Users\reactnative\navigate\node_modules\metro\src\DeltaBundler\traverseDependencies.js:261:33
at Generator.next (<anonymous>)
at asyncGeneratorStep (C:\Users\reactnative\navigate\node_modules\metro\src\DeltaBundler\traverseDependencies.js:87:24)

项目package.json依赖配置 #

{
  "name": "navigate",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node node_modules/react-native/local-cli/cli.js start",
    "test": "jest"
  },
  "dependencies": {
    "react": "16.6.3",
    "react-native": "0.58.5",
    "react-navigation": "^3.3.2"
  },
  "devDependencies": {
    "babel-core": "7.0.0-bridge.0",
    "babel-jest": "24.1.0",
    "jest": "24.1.0",
    "metro-react-native-babel-preset": "0.52.0",
    "react-test-renderer": "16.6.3"
  },
  "jest": {
    "preset": "react-native"
  }
}

内容的提问来源于stack exchange，提问作者Pooja Nandnikar