記錄一次RN的錯誤，However, this package itself specifies a `main` module field that could not be resolved
解決方案: 刪除Pods 目錄，重新pod install
我碰到 是pods目錄下多了react-native-camera ，導致jsload不過，刪除後重裝解決問題。
bundling failed: Error: While trying to resolve module `react-native-camera` from file `/Users/gfan/unicomWorks/code/conquerPro/runner/rn_modules/capacity/XYCamera.js`, the package `/Users/gfan/unicomWorks/code/conquerPro/runner/ios/Pods/react-native-camera/package.json` was successfully found. However, this package itself specifies a `main` module field that could not be resolved (`/Users/gfan/unicomWorks/code/conquerPro/runner/ios/Pods/react-native-camera/src/index.js`. Indeed, none of these files exist:
* `/Users/gfan/unicomWorks/code/conquerPro/runner/ios/Pods/react-native-camera/src/index.js(.native||.ios.js|.native.js|.js|.ios.json|.native.json|.json|.ios.ts|.native.ts|.ts|.ios.tsx|.native.tsx|.tsx)`
* `/Users/gfan/unicomWorks/code/conquerPro/runner/ios/Pods/react-native-camera/src/index.js/index(.native||.ios.js|.native.js|.js|.ios.json|.native.json|.json|.ios.ts|.native.ts|.ts|.ios.tsx|.native.tsx|.tsx)`
at ResolutionRequest.resolveDependency (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/node-haste/DependencyGraph/ResolutionRequest.js:65:15)
at DependencyGraph.resolveDependency (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/node-haste/DependencyGraph.js:283:16)
at Object.resolve (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/lib/transformHelpers.js:264:42)
at dependencies.map.result (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/DeltaBundler/traverseDependencies.js:399:31)
at Array.map (<anonymous>)
at resolveDependencies (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/DeltaBundler/traverseDependencies.js:396:18)
at /Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/DeltaBundler/traverseDependencies.js:269:33
at Generator.next (<anonymous>)
at asyncGeneratorStep (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/DeltaBundler/traverseDependencies.js:87:24)
at _next (/Users/gfan/unicomWorks/code/conquerPro/runner/node_modules/metro/src/DeltaBundler/traverseDependencies.js:107:9)