npm run dev:rn 编译成功后，React-Native启动失败

[flingInTheSky]

问题描述
创建一个项目后，执行npm run dev:rn后，可以编译成功，但是React-Native启动报错

复现步骤
[复现问题的步骤]

1. taro init demo
2. cd demo/
3. npm run dev:rn

期望行为
React-Native 正确运行

报错信息

Metro Bundler ready.

Loading dependency graph...(node:41249) UnhandledPromiseRejectionWarning: Error: `fsevents` unavailable (this watcher can only be used on Darwin)
    at new FSEventsWatcher (/Users/liushilou/Desktop/田姐/test/testz/node_modules/sane/src/fsevents_watcher.js:41:11)
    at createWatcher (/Users/liushilou/Desktop/田姐/test/testz/node_modules/jest-haste-map/build/index.js:572:23)
    at Array.map (<anonymous>)
    at HasteMap._watch (/Users/liushilou/Desktop/田姐/test/testz/node_modules/jest-haste-map/build/index.js:683:44)
    at /Users/liushilou/Desktop/田姐/test/testz/node_modules/jest-haste-map/build/index.js:280:21
    at processTicksAndRejections (internal/process/task_queues.js:85:5)
(node:41249) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:41249) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

系统信息

• 操作系统: [e.g. mac 10.13.6]
• Taro 版本 [e.g. v.1.3.11]
• Node.js 版本 [e.g. v12.7.0]
• 报错平台 [React-Native]

补充信息
在此之前，通过brew update && brew upgrate命令升级过

[taro-bot]

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Good luck and happy coding~

[taro-bot]

CC @Pines-Cheng

[Pines-Cheng]

参考一下这个issue：expo/expo#854

[flingInTheSky]

已解决，有些库安装失败了