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How to uninstall jest globally?

I've tried installing jest for testing react apps
After installing them with yarn, I'm unable to start my react app any way
I'm getting the below message, but it didn't work.
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": "^24.9.0"
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:
C:\Users\YV\node_modules\babel-jest (version: 27.0.5)
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:
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 C:\Users\YV\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!

I just had the same issue and fixed it. So, you probably installed jest globally on accident. In doing so, it likely ended up installed inside of users/yourname/node-modules/. If you can pull up a terminal, try doing a cd into node-modules from your home folder then do a ls -a. If you see babel-jest, do a rm -r babel-jest and rm -r jest. This fixed the problem for me. I'm running Linux, but the same strategy should work on Windows (not sure if the commands are exactly the same).

You probably installed a different global (npm install -g) version that is currently conflicting with the one you installed in your project.
You can quite literally delete the folder babel-jest inside C:\Users\YV\node_modules\ and try again. I would assume you're doing this by using create-react-app. Rest assured that Jest is already part of the installed dependencies (hence the message pointing to package-lock.json).

Can't change location of global npm packages to $HOME

I am trying to follow along with this Beginner's Guide to NPM and having trouble in the "Changing the Location of Global Packages" section. The goal in this section is to alter the location to which global Node packages are installed from root to $HOME/.node_modules_global.
Everything seems to work until I need to add .node_modules_global/bin to my $PATH environment variable, so that I can run global packages from the command line.
After including the following command to my .bash_profile file in $HOME...
export PATH="$HOME/.node_modules_global/bin:$PATH"
... I don't see the updated local path when running which npm.
Pictures of my previous output and my .bash_profile where I export the PATH: img1, img2
To clarify, I'm expecting the output of which npm to output /Users/mlongoria/.node_modules_global/bin/npm instead of /usr/local/bin/npm since I included the export PATH statement in my .bash_profile located in my /Users/mlongoria/ directory. Anybody know what I'm doing wrong here? I'm running OSX Catalina if it matters.

can you make sure npm is in your global npm/bin?
you can try ls $HOME/.npm_global and verify?
if you want to move npm there, you can install npm again by npm install npm -g, this will use the global npm folder and then after that, it will be picked up (try closing session and open new tab)

`npm install` is not installing local package's sub-dependencies

I have a package (package-a) that depends on another package (package-b) which is not published to npm but is on my file system. When I run npm install from package-a, package-b's dependencies are not installed. I have to navigate to package-b's directory and run npm install manually. Is there a way to install both packages' dependencies with a single npm command?
Here's my directory structure:
/
...
shared/
...
javascript/
...
package-b/
package.json
package-a/
package.json
Per the docs, I placed the following in package-a/package.json. (I'm using npm 5+)
dependencies: {
package-b: "file:../shared/javascript/package-b",
}
When I navigate to /package-a and run npm install, it installs all of package-a's dependencies like normal and also copies the package-b directory to package-a/node_modules. This is presumably what lets me type require('package-b') instead of require('../shared/javascript/package-b') .
However, as I stated before, package-bs dependencies are not installed, so if I try to use package-a, I get an error when package-b is required because it is trying to use dependencies that do not exist locally.
Once again, to solve this, I can navigate to package-b and run npm-install, but I'm hoping there's a better solution as I may have many such sub packages and I'd like to avoid having to write a shell script to go install all my dependencies if I can do this with an npm command. (perhaps I just did something wrong and npm install should be working?)
Follow up question: when I run npm install from package-b's directory, the packages are installed there, but not in the version of package-b that got copied to /package-a/node_modules during the first npm install, yet everything still works. So now it seems like when I require('package-b') it is actually resolving to /shared/javascript/package-b and NOT /package-a/node_modules/package-b. So what's the point of copying the file in the first place?
Update
It turns out this is a bug in npm 5. It only occurrs when installing from a package-lock.json file. (Github Issue)

The files are (probably) not being copied, they're being symbolically linked (symlink). This essentially creates an alias/shortcut that looks like a real directory, but points to another path.
This is how the older npm link feature worked. The reason is the code stays "live"; Changes in the linked module are reflected whenever you run the module that's referencing them, meaning you don't have to npm update all the time.

How can I test local installation of an NPM package I've published?

I recently published a package to NPM. The package works well on my own computer, where I wrote the code, but upon npm install on a coworkers machine, I start receiving errors.
What is the best way to go about installing and testing my package on my own computer? I could trace through the errors on my coworkers computer, but I assume there is a way I can do this on my own machine.

You don't have to install it on your own computer first if you want to test it, you could write unit tests instead, since you have to require the package if you do (just like an npm install).
Check the package.json to see if all needed modules are listed under dependencies. (Delete the node_modules folder, run npm install and see what errors are given)
If there is a file called .npmrc, check what files/folders it lists to make sure it's not excluding important files from NPM.
Make sure your module has a module.exports object, to be able to access the objects/functions
If this all didn't help, it might be a more specific problem and a GitHub link would help us more

Npm install global modules on different location node js

I am on a unix os, ubuntu, and I am experiencing a problem in installing global modules.
When I tried to look up where the node_modules folder is, I found out that npm installed some of my global modules in
/usr/lib/node_modules
and some of them are installed in
/usr/local/lib/node_modules
I have no problem before on using this global modules, until such time I tried installing a generator, that is when I first thought of looking into the directories because, after installing the generator, it says that I haven't installed the generator.
What is odd is that when I tried some of the modules, they work perfectly fine except for the other modules, saying it wasn't installed.
Is there a way to uninstall/remove/clean my computer from nodejs including its module and install it again so that it will just be using a single directory, so there won't be any confusion.
Why do you think npm installed this things in two diff. directories.

It looks to me like you have had 2 different versions of nodejs installed. Probably a packaged version and then a new release?
It works because your node folder is probably set to /usr/local/lib/node_modules
Node allways traverses the folder tree when looking for modules so if you do a require('imNotHere') it will look in:
/usr/local/lib/node_modules/imNotHere
/usr/local/node_modules/imNotHere
/usr/node_modules/imNotHere
/node_modules/imNotHere
before failing.
In your setup modules in /usr/lib/node_modules will still be caught by this