问题描述
我正在学习React，而我的英语却很差。我已经有两个React项目，但它们都不起作用:(我按照以下步骤操作，
npx create-react-app my-app cd my-app npm开始
但不起作用。我尝试清理缓存并再次安装npm，但未成功。我该如何解决？
> [email protected] start /Users/edu/Documents/htdocs/my-app
> react-scripts start
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": "8.0.5"
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/edu/node_modules/babel-loader (version: 8.1.0)
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/edu/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! [email protected] start: `react-scripts start`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] 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/edu/.npm/_logs/2020-09-17T00_43_20_777Z-debug.log
解决方法
看看输出中的建议6。
检查/ Users / edu / node_modules / babel-loader是否在项目目录之外。 例如，您可能不小心在主文件夹中安装了某些内容。
听起来好像您不小心在主文件夹（/Users/edu/）中而不是项目文件夹中安装了npm，并且您的项目正在依赖此依赖项。
解决方法是从/Users/edu/删除node_modules，package.json和package-lock.json，这些不需要在那里。
也许尝试：
npm cache clean
npm install
npm create-react-app my-app
cd my-app
npm run start