create-react-native-app无法正常工作

Question

每当我使用create-react-native-app启动一个项目并命令yarn启动时，都会出现以下错误：

error Command "start" not found.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

在此之前，当我命令 create-react-native-app 时，过程结束：

(node:7192) UnhandledPromiseRejectionWarning: Error: Cannot find module 'C:\Users\DELL PC\Desktop\Coursera WebDev\ReactNative\confusionAgain\node_modules\react-native-scripts\build\scripts\init.js'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Module.require (internal/modules/cjs/loader.js:692:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at _callee2$ (C:\Users\DELL PC\AppData\Roaming\npm\node_modules\create-react-native-app\build\index.js:128:32)
    at tryCatch (C:\Users\DELL PC\AppData\Roaming\npm\node_modules\create-react-native-app\node_modules\regenerator-runtime\runtime.js:62:40)
    at Generator.invoke [as _invoke] (C:\Users\DELL PC\AppData\Roaming\npm\node_modules\create-react-native-app\node_modules\regenerator-runtime\runtime.js:296:22)
    at Generator.prototype.(anonymous function) [as next] (C:\Users\DELL PC\AppData\Roaming\npm\node_modules\create-react-native-app\node_modules\regenerator-runtime\runtime.js:114:21)
    at step (C:\Users\DELL PC\AppData\Roaming\npm\node_modules\create-react-native-app\node_modules\babel-runtime\helpers\asyncToGenerator.js:17:30)
    at C:\Users\DELL PC\AppData\Roaming\npm\node_modules\create-react-native-app\node_modules\babel-runtime\helpers\asyncToGenerator.js:28:13
(node:7192) 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:7192) [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.

“我的项目”文件夹如下所示：

我尝试过的方法：

• 修改后的package.json： 来自此：

{
  "name": "confusion",
  "version": "0.1.0",
  "private": true,
  "devDependencies": {
    "react-native-scripts": "2.0.1"
  }
}

对此：

{
  "name": "confusion",
  "version": "0.1.0",
  "private": true,
  "devDependencies": {
    "react-native-scripts": "2.0.1"
  },
  "dependencies": {
    "react": "^15.4.2",
    "react-dom": "^15.4.2",
    "react-scripts": "^3.4.1"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  }
}

，然后命令npm start或yarn start，但是它说缺少索引文件。 请帮助，请。