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Need help on a react.js error that I keep on getting

Every time I try running npm start on a new project I keep on getting this error. Does anyone know or have any idea how to fix this??
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-jest": "^26.6.0"
Don't try to install it manually: your package manager does it
automatically. However, a different version of babel-jest was detected
higher up in the tree:
D:\node_modules\babel-jest (version: 24.9.0)
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:
Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
Delete node_modules in your project folder.
Remove "babel-jest" from dependencies and/or devDependencies in the package.json file in your project folder.
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:
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.
Check if D:\node_modules\babel-jest is outside your project directory.
For example, you might have accidentally installed something in your home folder.
Try running npm ls babel-jest in your project folder.
This will tell you which other package (apart from the expected react-scripts) installed babel-jest.
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!
react-portfolio#0.1.0 start: react-scripts start npm ERR! Exit
status 1 npm ERR! npm ERR! Failed at the react-portfolio#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!
C:\Users\smaso\AppData\Roaming\npm-cache_logs\2021-01-26T22_50_48_484Z-debug.log

I also face this problem. Simple solution of this problem is:
1)create .env file.
2) add SKIP_PREFLIGHT_CHECK=true in the file.
3) npm start

If this fails to work, create a .env file in the root directory of your project and add the following line
SKIP_PREFLIGHT_CHECK=true

just go to your project's root directory and delete node_module folder and npm start your project.

Delete and redownload node modules and run application again

To fix the dependency tree, try following the steps below in the exact order:
Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
Delete node_modules in your project folder.
Remove "babel-jest" from dependencies and/or devDependencies in the package.json file in your project folder.
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:
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.
Check if ./babel-jest is outside your project directory.
For example, you might have accidentally installed something in your home folder.
Try running npm ls babel-jest in your project folder.
This will tell you which other package (apart from the expected react-scripts) installed babel-jest.

Seems like you created the react project using create-react-app and installed jest using the following command.
yarn add --dev jest babel-jest #babel/preset-env #babel/preset-react react-test-renderer
But in the documentation it says just to run the following command if you are using create-react-app
yarn add --dev react-test-renderer
[See the documentation][1]https://jestjs.io/docs/tutorial-react
This worked for me.

I used the following command to uninstall jest npm uninstall jest in the root project folder (not the client) and then used the react scripts start command npm start and it worked

removing jest.config.js and uninstall ts-jest solved my problem

Fix the upstream dependency conflict installing NPM packages

I am trying to npm install vue-mapbox mapbox-gl, and I'm getting a dependency tree error.
I'm running Nuxt.js SSR with Vuetify and haven't installed anything related to Mapbox prior to running this install and am getting this error.
38 error code ERESOLVE
39 error ERESOLVE unable to resolve dependency tree
40 error
41 error While resolving: [1mexample[22m#[1m1.0.0[22m
41 error Found: [1mmapbox-gl[22m#[1m1.13.0[22m[2m[22m
41 error [2mnode_modules/mapbox-gl[22m
41 error [1mmapbox-gl[22m#"[1m^1.13.0[22m" from the root project
41 error
41 error Could not resolve dependency:
41 error [35mpeer[39m [1mmapbox-gl[22m#"[1m^0.53.0[22m" from [1mvue-mapbox[22m#[1m0.4.1[22m[2m[22m
41 error [2mnode_modules/vue-mapbox[22m
41 error [1mvue-mapbox[22m#"[1m*[22m" from the root project
41 error
41 error Fix the upstream dependency conflict, or retry
41 error this command with --force, or --legacy-peer-deps
41 error to accept an incorrect (and potentially broken) dependency resolution.
41 error
41 error See /Users/user/.npm/eresolve-report.txt for a full report.
42 verbose exit 1
What's the right way to go about fixing this upstream dependency conflict?

It looks like it's a problem with peer dependencies in the latest version of npm (v7) which is still a beta version.
Try with npm install --legacy-peer-deps. For detailed information check the blog post npm v7 Series - Beta Release! And: SemVer-Major Changes in npm v7.

Use --legacy-peer-deps after npm install. For example, if you want to install Radium, use:
npm install --legacy-peer-deps --save radium

There are two ways:
use npm install --legacy-peer-deps to install, and if this doesn't work use
the force method. Add --force next to npm install: npm install --force

You can follow these commands
First type:
npm config set legacy-peer-deps true
Then type:
npx create-react-app my-app

Your dependency mexample requires mmapbox-gl v1.13.0 and mvue-mapbox requires mmapbox-gl v0.53.0.
NPM doesn't know which version to install, so it gives a warning. You can bypass the errors using -- force or --legacy-peer-deps, but you are ignoring an error, and making unexpected results.
Production Options:
Probably one of your packages is outdated. Upgrading packages and fixing upgrade errors might fix the dependency conflict.
Overriding a dependency manually to avoid the warning and error. You are setting the version to a specific one that you know that works. Usually the newer version.
Example solution with override. Your package.json file will look like this:
{
"name": "my-app",
"version": "0.1.0",
"private": true,
"dependencies": {
"mexample": "^1.2.0",
"vue-mapbox": "*"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},
"overrides": {
"mmapbox-gl": "1.13.0"
}
}
The last option is bypassing using either:
--legacy-peer-deps completely ignores all peerDependencies using the newest version without pinning on file package-lock.json
--force forces the use of the newest, pinning all the versions on package-lock.json
Extra: You shouldn't use "*" as a version, because it might update major and break dependencies.

Until npm version 7.19.1, it still had the same issue. After upgrading to version 7.20.3, use command npm install -g npm#latest and npm audit fix. All packages will be fixed without error.

I tried multiple ways, but nothing was working for me. At last I tried this and it worked:
npm config set legacy-peer-deps true
Run this in the project folder and then try to install any package. It might work for you as well.

To solve it, fix the upstream dependency conflict installing NPM packages error
Method 1. Just use --legacy-peer-deps after npm install.
For example, if you want to install Axios, use
npm install --legacy-peer-deps --save axios.
Method 2. Updating npm and 'audit fix'
npm I -g npm#latest
npm audit fix --force
Method 3. Using --force to install packages
npm install axios --force

I was stuck on this issue for long which also makes error from other commands which calls for some install commands that was breaking.
The only solution that works (maybe suppresses the error) is
npm config set legacy-peer-deps true
This will set the configuration of legacy-peer-deps to true

To resolve npm dependencies and conflicts with npm packages, use npm-check-updates.

Almost all answers here suggest using force or legacy-peer-deps. Though this will technically work, please note that this is not recommended by NPM if you can avoid it anymore (source). Some folks may not have a choice, but I was able to resolve my dependency conflicts by deleting node-modules and package-lock.json then manually updating packages to their latest version one at a time until it stopped complaining (packages mentioned in the error messages after running npm i. Not a great or clean solution, but at least my packages are up-to-date and I'm not ignoring errors or using legacy solutions.

A lot of upvotes for using --legacy-peer-deps, but if --force works, I would recommend using that since it still pins many dependency versions while --legacy-peer-deps ignores peer dependencies entirely. See the example below:
npm: When to use --force and --legacy-peer-deps
I started getting this error on Azure DevOps a few days ago. I initially thought it was a glitch on the Azure side, but since it continued, we started looking into it a bit more.
It turns out the agent we are using, windows-2022, was updated a few days ago:
Updating readme file for win22 version 20220607.3 (#5713)
Node and NPM now match the latest Node.js LTS version: 16.15.1 (includes npm 8.11.0)
Downloads
You can view all agents-included software on Microsoft-hosted agents, Software.
After reading on Microsoft Visual Studio Developer Community, they recommend downgrading Node.js using Node.js Tool Installer task like this:
- task: NodeTool#0
inputs:
versionSpec: '16.14.2'
Node.js Tool Installer task
npm install fails in Azure DevOps Hosted Agent
However, we decided that we do not want to downgrade Node.js, so the first step was matching Node.js locally with LTS version 16.15.1 and npm 8.11.0.
When running npm ci, we then got the same error locally.
We tried npm ci --force and we then got this error:
npm ci can only install packages when your package.json and
package-lock.json or npm-shrinkwrap.json are in sync. Please update
your lock file with npm install before continuing.
npm install gave the same error even after node_modules was manually removed, but npm install --force worked, and it generated a new package-lock.json file.
npm ci still failed with the same error, but running npm ci --force worked. We decided to update Azure DevOps .yml to include --force and checked in the new package-lock.json file. After doing this, everything worked like before and we could now update our packages one by one.

delete the package-lock.json file
modify the package.json file, updating the version as indicated by the peer dependency
Add a tilde or caret for allowing install latest version and resolving dependency issues, for example :
~1.0.2 means to install version 1.0.2 or the latest patch version such as 1.0.4.
^1.0.2 means to install version 1.0.2 or the latest minor or patch version such as 1.1.0.
run npm install or npm udpate

I resolved this by adding
steps:
- task: NodeTool#0
inputs:
versionSpec: '12.x'

Nothing here worked for me.
After struggling with this issue for so long, I found a solution that worked.
Apparently I had some packages installed globally.
Listed them with:
npm list -g --depth=0
Then removed the unwanted packages with:
npm uninstall -g <package-name>
Finally I got the problem fixed

npx create-react-app gives error when running npm start

I'm having an issue with the create-react-app command. I've followed the instructions twice, tried other solutions such as adding
"resolutions": {
"ajv": "6.8.1"
}
to the package.json file then uninstalling and reinstalling ajv#6.8.1. I've tried using yarn but ended up just starting it all over to use npm, just to get the same error. Most answers I am finding are a year or more old. any help is Appreciated!
Here is the error message..
npm start
scilenceapp#0.1.0 start C:\Users\chris\OneDrive\Documents\coding stuff\SciLence\ScilenceApp\scilenceapp
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": "4.42.0"
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:
C:\Users\chris\node_modules\webpack (version: 4.41.2)
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:
Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
Delete node_modules in your project folder.
Remove "webpack" from dependencies and/or devDependencies in the package.json file in your project folder.
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:
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.
Check if C:\Users\chris\node_modules\webpack is outside your project directory.
For example, you might have accidentally installed something in your home folder.
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! scilenceapp#0.1.0 start: react-scripts start
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the scilenceapp#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! C:\Users\chris\AppData\Roaming\npm-cache_logs\2020-07-27T21_42_25_489Z-debug.log
PS C:\Users\chris\OneDrive\Documents\coding stuff\SciLence\ScilenceApp\scilenceapp>

“C:\Users\chris\node_modules\webpack (version: 4.41.2)”
You may have to remove that file from your c drive. And run npm i again. I had the same issue with jest.

try also npm cache clean --force

create-react-app always throws babel error

Every time I create a create-react-app project it throws this error:
The react-scripts package provided by Create React App requires a dependency:
"babel-loader": "8.0.4"
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/dalegrant/Desktop/hyberchat-dashboard/client/node_modules/babel-loader (version: 8.0.5)
I have tried downgrading to 8.0.4,
I've tried installing 8.0.5
I've even made sure all my dependencies for babel rely on a 8.0.5!
I have no idea what to do from here as the error persists for every create react app I now build!
This must be a common problem, does anybody have an idea on how to get around this?!

In your machine user folder there is a node_modules directory and package-lock.json remove them using rm -rf User/node_modules and rm -rf User/package-lock.json after that delete node_module directory and pack-lock.json file in your project run npm install again then it's works

Remove the babel-loader package (also globally):
npm uninstall babel-loader
npm uninstall babel-loader -g
Then run create-react-app again, it should install the correct dependency.
If you use the babel-loader somewhere else, pin the dependency there to ensure this problem does not happen again.

you probably installed node_modules in your main folders before. Search for them and remove.
In my case i have installed node_modules on my Home folder. When i removed files from this directory problem disapeared

Is it possible to generate a `yarn.lock` file without installing the packages?

I need to generate a yarn.lock file from my package.json but I want to avoid node_modules creation. Is it possible?

EDIT: Please check the comment below for a solution without the need for any additional package thanks to #talon55 : npm install --package-lock-only; yarn import
Old answer:
This is actually one of the few features that NPM has (npm install --package-lock-only) and Yarn does not support.
It is a heavily requested feature as you can tell from these 2 open Github issues: 5738 and 2340
I stumbled upon the command yarn generate-lock-entry documented in here but it definitely does not do what we are looking for.
The workaround I would suggest is generating an NPM lock file and converting it to a yarn.lock file using synp:
npm install -g synp
npm install --package-lock-only
synp --source-file package-lock.json
Please note that Synp requires the the packages to be installed and that the node_modules is rightly populated. This may, or may not be, a problem to your use case.

Available since yarn v3.0.0-rc.10
yarn install --mode update-lockfile

yarn generate-lock-entry > yarn.lock