Cannot uninstall webpack from react-script

问题:

I was trying to make a todo-app in react, which is new to me. But after once installed webpack, npm start doesnt working. It gives me:

my-todo-react@0.1.0 start /home/hanna/Desktop/projects/my-todo-react 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": "4.19.1"

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:

/home/hanna/node_modules/webpack (version: 4.20.2)

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

If 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 /home/hanna/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! my-todo-react@0.1.0 start: react-scripts start npm ERR! Exit status 1 npm ERR! npm ERR! Failed at the my-todo-react@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/hanna/.npm/_logs/2018-10-02T10_39_06_361Z-debug.log

回答1:

Create a .env file in the root directory of the project and add this line SKIP_PREFLIGHT_CHECK=true inside the file.

then try to run yarn start.

回答2:

To solve this issue I had to uninstall webpack and webpack-dev-server from the node-modules folder and then install them again but with different versions.

1. Open cmd on the node-modules folder outside of your project folder

2. Uninstall webpack and webpack-dev-server:

   npm uninstall webpack
   npm uninstall webpack-dev-server
   

3. Delete the node-modules folder and the package-lock.json file from your project's folder.

4. Open the node-modules again

   npm install webpack@4.19.1
   npm install webpack-dev-server@3.1.9
   

5. Use this command on your project folder

   npm install
   

It did the trick for me, hope it helps you too.

回答3:

I had similar problem today. I resolved with the following steps:

1. Execute npm ls webpack --> to find out that I have installed Webpack outside my folder ("like yours ... /home/hanna/node_modules/webpack).
2. Then cd into that location (/home/hanna/node_modules/) and execute npm install webpack@4.19.1. That way I have the same version of Webpack like in my project folder.

After that, when I run npm start, it works fine.

回答4:

Since it looks like the project uses Create React App, Webpack is probably already a dependency in the package.json. So the easy way to install it is to just go to the project directory and type npm install (or yarn install) in the terminal.

If using the Webpack CLI causes errors, it's probably because there's a different version installed globally.

To uninstall it globally, type npm -g uninstall webpack.

回答5:

One solution I had was to go to my "Home" folder and delete the node_modules folder and package-lock.json file.

Worked afterwards.

回答6:

Go to your project directory where you are running npm start and run the command

touch .env

If there is no pre-existing .env file in your project this will create it. Got to .env file and add the following code (if you are on LINUX box you do this by typing nano .env otherwise just use a text editor. SKIP_PREFLIGHT_CHECK=true

Save the file and try running npm start again. This solution is exactly what is suggested in the error message and it worked for me

回答7:

Go to /home/hanna and type npm i webpack@required_dependency. It should solve your problem.

回答8:

If someone still facing this issue and uses yarn instead of npm can do (I am a mac user):

• Open a terminal
• Type yarn remove webpack
• Come in to your project directory using your file explorer
• Delete everything there
• Open your code-editor
• Delete hidden filers (ETC: .env or .gitignore files) if exists
• In your project directory open a terminal and type npx create-react-app . and hit enter.
• And restart the app typing yarn start after download.

It worked for me. It downloaded the web pack which is needed from react-scripts.

回答9:

I encountered the same issue and following worked for me:

• Delete the node-modules folder and package-lock.json file
• Downloaded and installed Node.js
• npm install webpack@4.19.1
• npm install webpack-dev-server@3.1.9
• Deleted babel-eslint entry from package.json
• Used this command on the project folder: npm install
• Finally yarn start or npm start

回答10:

do this

first code in terminal this -->

 yarn add --dev dotenv

create .env file in root directory then add below line in the .env file

 SKIP_PREFLIGHT_CHECK=true 

回答11:

Your problem is you installed webpack version: 4.20.2

You need to install an earlier version "webpack": "4.19.1"`

Your problem is you installed webpack version: 4.20.2

You need to install an earlier version "webpack": "4.19.1"` ..So

$npm uninstall -g webpack

and

$npm install -g webpack@4.19.1

Hope that helps

回答12:

I think if you have a webpack package installed globally it might cause such error. Removing it globally might solve the problem. That's what I did here and it works.

回答13:

Due to newer versions, this worked for me:

1. Open a terminal window (command prompt) on the node_modules folder outside of your project folder

2. Uninstall webpack and webpack-dev-server:

   npm uninstall webpack
   npm uninstall webpack-dev-server
   

3. Delete the node_modules folder and the package-lock.json file from your project's folder.

4. Open node_modules again

   npm install webpack@4.28.3
   npm install webpack-dev-server@3.1.14
   

5. Use this command in your project folder:

   npm install
   

回答14:

I couldn't find a way to uninstall the whole node module folder the only way is to delete the whole file using command line

rm -rf node_modules

回答15:

I think if you have a webpack package installed globally it might cause such error. Removing it globally might solve the problem. That's what I did here and it works.

npm uninstall webpack
npm uninstall webpack-dev-server

Delete the node_modules folder and the package-lock.json file from your root directory

##thompsonmax## 

Then you can now run your command to your app,

create-react-app react-app