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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

Cannot install my own npm package

I've been developing a later-to-be-release Open Source project with Node as a CLI tool. The CLI itself works great I only need to test if it works while on another project, so for that I installed the projects globally npm install -g without errors, but for the life of me I can't use the CLI.
I get the following error:
The odd thing is that the directory and file does exist in the global npm folder:
This is the project's package.json:
Am I not understanding how making a npm/node CLI works? What I'm missing?
EDIT 1:
This is my index.js file:
And this is the commander.js file:
EDIT 2:
After creating a test project as #AngYC suggested I could use the test cli successfully, while inspecting the difference I found this. Inside C:\Users\Ivan\AppData\Roaming\npm the .cmd of both projects are quite different:
EDIT 3 (Solution):
After fiddling around I found out that the file that really needed the shebang (#!/usr/bin/env node) was only index.js file and not the commander.js one. Removing the shebang in that file solved the problem

You may want to try to link your local package to your global executable list.
https://docs.npmjs.com/cli/link
All you have to do is run npm link in the folder you got your tool and it should make the command available globally.

Try to uninstall cli run npm rm -g cli or sudo npm rm -g cli. Then you run: npm install cli -g
If the problem persist, you might want to remove you npm package globally, probably there might be some conflicting things running.
Type this: %appdata% (either in explorer, run prompt, or start menu).
You can simply remove all globally installed npm packages by deleting the contents of:
C:\Users\username\AppData\Roaming\npm
Then you might also want to clear all the your cache run npm cache clear or npm cache clear --force as the case might be.
Then you reinstall all your packages that were install globally again.
If problem still persist, check this:
When you run npm root -g, it yields C:\Users\<username>\AppData\Roaming\npm\node_modules, or even, you should check your path maybe the executable binaries and .cmd files end up in C:\Users\<username>\AppData\Roaming\npm instead of C:\Users\<username>\AppData\Roaming\npm\node_modules, you will need to add that path to the PATH env. variable.
I hope this resolves your issue.

cannot found lodash in npm installation

I installed lodash and several other libraries this way:
npm install grunt-contrib-jshint --save-dev
npm install grunt-contrib-testem --save-dev
npm install sinon --save-dev
npm install -g phantomjs
npm install lodash --save
npm install jquery --save
When I run testem using grunt (or directly), I found the following problem
ReferenceError: _ is not defined
Digging into the issue, I found the issue in the mode following line
module.exports = require('./lodash');
(I have to point that the ./ is added by the installer. I even tried to remove it, but the error persist)
This is located on index.js, inside the node_modules/lodash folder
I think this is an issue of installation, but no matter what I do, it continue failing. I update npm, I remove node_modules and install all over again, but this continue happens.
Any advice or clue will be greatly appreciate

You don't need to pass the relative path of modules that are inside the node_modules directory, just passing the module name will do the trick:
require('lodash');
Now node.js will automatically look inside the node_modules directory for you, simple as that <3.

Why is it necessary to install Browserify twice to bundle

I created a new project
I npm install -g browserify
I tested using the cmdline, browserify app.js > bundle.js. Cool.
I want to minify so I npm install uglifyify --save-dev
I tested using the cmdline, browserify -g uglifyify app.js > bundle.js. Great.
Now I want to do this with code, but I get Error: Cannot find module 'browserify'
This is my code, basically to replace the cmdline
var browserify = require('browserify')
var fs = require('fs')
var bundler = browserify('./app.js')
bundler.transform({
global: true
}, 'uglifyify')
bundler.bundle()
.pipe(fs.createWriteStream('./bundle.js'))
It seems I would need to again install browserify locally to this project?

Installing an npm module like browserify allows you to use browserify as a command on the command line. To use the module within your project's code, you must install the module as a dependency. In other words, yes, is must be installed locally within the project's ./node_modules folder and referenced in the package.json file.
From the npm documentation:
Local install (default): puts stuff in ./node_modules of the current package root.
Global install (with -g): puts stuff in /usr/local or wherever node is installed.
Install it locally if you're going to require() it.
Install it globally if you're going to run it on the command line.
If you need both, then install it in both places, or use npm link.

As said in the other answer, one way to solve this is that you can install browserify locally instead of globally, like: npm install --save browserify uglifyfy. Then you can add a script in package.json:
...
"scripts": {
"build": "browserify app.js > bundle.js",
...
},
...
Now, npm run-script build will know how to find local browserify, which is going to be in your node_modules/ directory. And your require('browserify') will work, since browserify is now local.
Another way you could solve this is NODE_PATH env variable. Set this variable in your bashrc or equivalent like this:
export NODE_PATH=$NODE_PATH:$HOME/.nvm/versions/node/v4.2.6/lib/node_modules
Adjust the path to wherever your global node_modules are. Then you can require() whatever you installed with -g flag in your code.
However this is suboptimal, as it can lead to errors and misunderstandings. But if it's for some quick-and-dirty scripts, it can help.

How do I use GruntFile.coffee and package.json to extract/make/fetch/?? the Lungo.js example files?

I am wanting to try out the Lungo.js examples from here : https://github.com/tapquo/Lungo.js,
however the index.html in the example directory is expecting files in the components and package directories and, while those directories do exist as part of this bundle, they are empty of any files.
I have a GruntFile.coffee and a package.json and I believe that together these are some kind of make file that perhaps should make/pull/create the files that the example needs to run, but I don't know how to make them do that.
I have installed the following:
sudo npm install -g grunt-cli
sudo npm install -g grunt
sudo npm install -g coffee-script
I can now run "coffee GruntFile.coffee" successfully, but it does nothing I can see, certainly it is not creating the missing files.
And the "grunt" command simply says "Fatal error: Unable to find local grunt."
How do I tell this bundle of code that I have to get the other files I require?
And, bonus question, what's going on here?
(I understand javascript, and pulling code from github, but not these other frameworks)

package.json has devDependencies field. They need to be installed before you may use grunt command. First you need execute
npm install
in directory wich contains it.
There is definitely bug in this line of Gruntfile
You should change it to:
pkg: grunt.file.readJSON "package.json"
Then, after local grunt is installed, you may run
grunt
which will execute default task. This is well known practice last time.

You need to install grunt locally, not globally. Only grunt-cli should be installed globally.
So instead of
npm install -g grunt
Navigate to your project root folder and execute
npm install grunt
There's a getting started guide on the Grunt homepage.
The package.json file is a descriptor file for your application. More information on this file can be found in this interactive guide. You normally use grunt together with this file so you can list your grunt plugins as dependencies of your application. I suggest reading a tutorial on grunt to learn how it works.