使用 npx create-react-app 创建的应用无法启动，

Question

祝你好运

几个月前，我通过 create-react-app 创建了一个应用程序。当我进入 npm start 时，这个应用程序没有运行。我收到以下错误消息：

react-scripts 开始

There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "babel-loader": "8.1.0"

Don't try to install it manually: your package manager does it automatically.
However, a different version of babel-loader was detected higher up in the tree:

  /Users/kevinmotzkus/Documents/projects/node_modules/babel-loader (version: 8.0.6) 

Manually installing incompatible versions is known to cause hard-to-debug issues.

If you would prefer to ignore this check, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project.
That will permanently disable this message but you might encounter other issues.

To fix the dependency tree, try following the steps below in the exact order:

  1. Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
  2. Delete node_modules in your project folder.
  3. Remove "babel-loader" from dependencies and/or devDependencies in the package.json file in your project folder.
  4. Run npm install or yarn, depending on the package manager you use.

In most cases, this should be enough to fix the problem.
If this has not helped, there are a few other things you can try:

  5. If you used npm, install yarn (http://yarnpkg.com/) and repeat the above steps with it instead.
     This may help because npm has known issues with package hoisting which may get resolved in future versions.

  6. Check if /Users/kevinmotzkus/Documents/projects/node_modules/babel-loader is outside your project directory.
     For example, you might have accidentally installed something in your home folder.

  7. Try running npm ls babel-loader in your project folder.
     This will tell you which other package (apart from the expected react-scripts) installed babel-loader.

If nothing else helps, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project.
That would permanently disable this preflight check in case you want to proceed anyway.

P.S. We know this message is long but please read the steps above :-) We hope you find them helpful!

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! womd@0.1.0 start: `react-scripts start`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the womd@0.1.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/kevinmotzkus/.npm/_logs/2020-07-10T20_09_39_848Z-debug.log

我按照步骤操作，但它不起作用。我不知道要找什么。

我需要将包管理安装到应用程序文件夹中吗？我对反应和编码有点陌生，所以请耐心和温柔^^

如果你也对我的问题提出批评，我很高兴，这可以理解吗，你需要更多或具体的信息吗？

Answer 1

你可以删除 package-lock.json 文件和 node_modules 文件夹然后运行

npm install

另外，这是一个非常相似的问题 Create React App requires a dependency: “babel-loader”: “8.1.0”