使用 create-react-app 创建的 React 应用程序无法启动，returns 错误

Question

我使用 create-react app 创建了一个新的 React 应用程序，当我尝试使用命令 npm start 启动它时，它 returns 出现以下错误：

> warbler-client@0.1.0 start 
/mnt/c/Users/Debchakra/Desktop/warbler/warbler-client
> 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:

  "webpack": "4.28.3"

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

  /mnt/c/Users/Debchakra/node_modules/webpack (version: 4.29.5)

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 "webpack" 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 /mnt/c/Users/Debchakra/node_modules/webpack is outside your 
project directory.
     For example, you might have accidentally installed something in your 
home folder.

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

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! warbler-client@0.1.0 start: `react-scripts start`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the warbler-client@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!     /home/webdeb/.npm/_logs/2019-03-26T06_44_19_294Z-debug.log

我尝试了上面提到的所有步骤，比如安装 yarn 等等，但它总是显示相同的错误。

以前，我在 if cloud9 中使用了 create-react-app，当时它运行良好，但现在我在本地系统上进行。我实际上使用的是 WSL。（如果有帮助的话）

Answer 1

您已经在系统上全局安装了一个版本的 webpack（/mnt/c/Users/Debchakra/node_modules/webpack (version: 4.29.5) ) 与 create-react-app 要求的版本不匹配。

通过 npm uninstall -g webpack 卸载全球版本应该可以解决这个问题。

使用 create-react-app 创建的 React 应用程序无法启动，returns 错误

React app created using create-react-app failing to start, returns error

reactjs

npm-start

create-react-app

yarnpkg