Develop Reference

NPM Install giving rollbackFailedOptional

After trying to use the Windows Powershell (as an admin), the command prompt (as an admin) and the bash CMD; I repeatedly get the following error after trying an npm install command:
npm install npm#latest -g
is the attempted command and...
[...] / rollbackFailedOptional: verb npm-session xxxxxxxxxxx
where the 'x's represent different letter and number combinations at each attempt, is the message. I am aware that this should be the first step in the installation of a package but it remains on this message for a long time and will not change.
I am trying to use the JavaScript React library, more specifically the 'create-react-app'. The npm install -g create-react-app command is also causing the error.
npm version: 6.5.0
npx version: 10.2.0
node version: 10.15.0
A solution would be greatly appreciated.

https://docs.npmjs.com/try-the-latest-stable-version-of-npm In this link there is the documentation for updating npm version for windows with a link to a tool developed by Microsoft to update npm (https://github.com/felixrieseberg/npm-windows-upgrade)

I found the solution:
As my device username has both my first and last names, with a space in between, npm was reaching errors because of this. So the solution was to uninstall node from the default location and reinstall it in a folder on my C:\ drive, where there were no files in the directory that have spaces in the names. I then changed the cache location into this same C:\ drive folder, and the problem was solved.
npm config set cache C:\NODEJS\npm-cache
(these folders must be created before you can set the config directory to these.)

For me, I ended up having to:
Uninstall Node.js
Remove the folder "nodejs" completely from C:\Program Files (or
wherever you decided to install node)
Reinstall Node.js
After that, I did not encounter [...] / rollbackFailedOptional: verb npm-session xxxxxxxxxxx anymore.
I'm not quite sure what the issue was but all suggestions I found on stack did not solve this problem for me. I hope this helps someone.

Check if you are connected to any other VPN or proxy setting. If so try to disable it or disconnect from it and then execute the npm command. It worked for me. In my case, I was using the organization laptop and was connected to external vpn network, so i disabled the vpn and tried the command and it worked.

In our case the hard disc of the nexus server (repository server) was just full. Maybe someone helps this. Before looking into other more complicated options.

for my case i uninstalled the reinstelled it and used powershell insted of cmd and it worked like a charm

First run these commands.
npm config rm proxy
npm config rm https-proxy
then run this.
npm config set registry https://registry.npmjs.org/
check if the internet is connected
and try to run the npm command which was giving the error.

Yarn global command not working

I'm working with Yarn v0.16.1. If I understand correctly (according to the documentation), yarn global add <package> should be the equivalent of npm install -g <package>. However, when I run the example in the docs (with create-react-app), the command runs successfully but create-react-app is then not available from the command line. Here's the output:
$ yarn global add create-react-app
$ yarn global v0.16.1
[1/4] 🔍 Resolving packages...
[2/4] 🚚 Fetching packages...
[3/4] 🔗 Linking dependencies...
[4/4] 📃 Building fresh packages...
success Installed create-react-app#0.6.0 with binaries:
- create-react-app
✨ Done in 3.22s.
$ create-react-app --help
-bash: create-react-app: command not found
Doing a global install with npm has the expected result, and everything works. What am I missing with yarn?

You should add export PATH="$PATH:$(yarn global bin)" to your ~/.bash_profile or whatever you use. It would solve the issue.
Depending on how you installed it, Yarn's global folder varies for some reason. You can follow this issue here.

Update Dec 2018
Just updating the path didn't work for me. I had to also set the yarn prefix.
Ubuntu 18.04.1 LTS (bionic)
yarn 1.12.3
npm v3.5.2
node v8.10.0
zsh 5.4.2
Steps
Confirm your global bin path
yarn global bin
I got: /home/username/.yarn/bin
set yarn prefix:
make sure your yarn prefix is the parent directory of your bin directory. You can confirm by running
yarn config get prefix
when I ran this, my prefix was empty, so I set it:
yarn config set prefix ~/.yarn
add the following to ~/.bash_profile or ~/.bashrc
export PATH="$PATH:`yarn global bin`"
for zsh users, be sure to add this line to ~/.zshrc
restart your shell or start a new one
bash -l or zsh

In my case yarn global bin wasn't working.
Try a brew reinstall yarn if that's how you installed yarn
👍🏻

Ran into this issue but on a Windows system. All I had to do was add the yarn global bin to the PATH variable.
setx path "%path%;c:\users\YOURUSERNAME\appdata\local\yarn\bin"
Remember to change YOURUSERNAME to your account username.
You can check where your global bin is by running
yarn global bin
And please don't forget to restart the CMD window that you're working on.
Happy coding!
! WARNING !
When executing the command that %path%; in front of your yarn directory is very important. If you don't type it you will definitely replace all your system environment variables.
Option 2
Safer option would be would be to just go to System Properties > Advanced > Environment Variables > select PATH the click Edit > then append and not replace with ;c:\users\YOURUSERNAME\appdata\local\yarn\bin

For macOS, you just need one step,
export PATH=~/.yarn/bin:$PATH

To reinstall run below.
brew install -g yarn
// Note:(updating homebrew) for Mac users.
brew reinstall yarn
// (if yarn is still not found)

Here's the process I used on Mac OSX El Capitan.
Try to install yarn (I used the Curl command) if you have it already. This will bring up if its already installed and will give you the current directory where it exists.
Like this:
curl -o- -L https://yarnpkg.com/install.sh | bash
It will display something like this:
Installing Yarn!
> /Users/{Your Username}/.yarn already exists, possibly from a past Yarn install.
> Remove it (rm -rf /Users/{Your Username}/.yarn) and run this script again.
Do not remove it. Move on to step 2.
Copy the directory listed above. Open your profile. I'm using zsh. So mine was ~/.zshrc. You can find yours and more info here.
Copy the following (replacing your directory and username details as necessary, the one you got from the installation error message).
alias yarn="/Users/{Your Username}/.yarn/bin/yarn"
Try to run yarn version to check if its working. If it is, you should see a version number displayed in your terminal.
That's it, and what worked for me.

AndrewD gave a great answer, but for those on Windows it's a bit different, especially step 3.
Please do not use the command setx as #Thapedict said.
It will remove all your previous paths you had and replace it with only the given directory.
If you want to use setx, I think there might be a flag to make it append the existing path variables, but I don't know which one. Using only setx will not append to it.
I would just do System Properties > Advanced > Environment Variables > Edit Path > New > c:\users\YOURUSERNAME\appdata\local\yarn\bin
to make sure you don't remove your previous variables.

export PATH="$PATH:$(yarn global bin)"

On Ubuntu, I fixed by installing the package like this:
sudo yarn global add <package> --prefix /usr/local

When switching from bash to zsh, I got the same error, it worked for me:
in your .zshrc
# NVM Stuff
export NVM_DIR="$HOME/.nvm"
. "$(brew --prefix nvm)/nvm.sh"
# YVM Stuff
export YVM_DIR="$HOME/.yvm"
. "$(brew --prefix yvm)/yvm.sh"
As I understand it, my mistake arose due to the lack of access to version managers

I faced a similar issue on Windows after installing Yarn then Vue Cli.
Packages were installed but not accessible.
The problem was that the directory where yarn packages are installed is not in PATH.
The default installation directory for Yarn packages in my case was
C:\Users\USERNAME\AppData\Local\Yarn
So make sure to add this directory to path.

Putting this answer so that hopefully it can come in google and help others.
expo command not found after using
yarn global add expo-cli don't work in ubuntu 20.04

It's no longer necessary to modify your path for yarn
Newer versions of yarn include yarn create and yarn exec
In the case of create-react-app you can run yarn create react-app see this blog post https://classic.yarnpkg.com/blog/2017/05/12/introducing-yarn/
To run a non-creating package like serve, you can still run it without modifying your path! After installing it with yarn global add serve try this: yarn exec serve

How to install Node.js or npm on Xampp

I'm new, so please excuse any mistakes.
I am trying to develop a web application locally using XAMPP. I intend to deploy using a hosted web service. XAMPP was a very convenient way to get me up and programming without any fuss.
There are several github javascript libraries that look like they can only be installed with npm. Does this mean that I cannot use them? The specific one that I'm currently having a problem with is: https://github.com/selz/plyr. Or, is it possible to install npm on my XAMPP server? I have a windows machine.
Thank you very much in advance for your help.

is it possible to install npm on my XAMPP server
You will not be installing NPM on your server, you will be installing it on your machine (think of it as a regular program you install on your PC) (if your server happens to be your PC as well, then, well, you are technically installing it on your server)
In order to be able to use NPM though, since NPM is written in JavaScript, you will need to install Node.js, also on your machine.
So, head over to the Node.js site and download and install Node. NPM is included in the installer and will be installed alongside Node.
After that is done, installing NPM packages is simply a matter of heading to your desired directory and executing npm install <PACKAGE_NAME> there.
In general, XAMPP helps you with your back end. Not your front end.
Useful links:
https://docs.npmjs.com/

Does this mean that I cannot use them?
No. You can install node at https://nodejs.org and then use npm through your windows command line to install packages. To test this, just
Install NodeJS
Open Command Line
Make a new folder under your user folder called test mkdir test
cd into that folder on Windows Command Line cd test
Create a new project with npm init -y *note this creates a
package.json file for you
Now you start installing packages with npm install <package>
--save * --save saves the package info in your package.json file (recommended). There is also -g wihch means the package will
be installed globally (usually you don't want this and only want it
locally to your project).
That's how you use NodeJS. If you want to use that with XAMPP then you need to do the same thing but instead of using your user folder (C:\users\yourname) you need to use the htdocs folder of XAMPP (usually C:\xampp\htdocs)

Trouble installing a module as a global variable -- /usr/bin/env not a directory

I am attempting to install the node.js module 'javascripting' (source code can be found: https://github.com/sethvincent/javascripting) and have been unable to install it as a global variable to run through the terminal.
After installing node.js I attempted to install javascripting with the line: npm install --global javascripting
While it is my understand that this should work, it only downloads the module but does not set it as a global variable to be run in terminal.
The error I receive when attempting to run it as a global variable is "/usr/bin/env: node: No such file or directory".
After receiving this error I attempted to move the module to /usr/bin/env from the directory it installed in (usr/local/lib/node_modules/javascripting). Unfortunately, I was not able to move the files because /usr/bin/env is not a directory, rather it seems to be some sort of executable java file (usr/bin is a directory).
I am a bit lost and would love some advice on either how to install the module as a working global variable or whether there is another way to run the module without installing it as a global variable.

This will happen if the node.js binary (node) is not installed in the $PATH anywhere.
if you run env node by itself, you will get the same error. It looks like this may be an Ubuntu bug: https://github.com/joyent/node/issues/3911
Try sudo ln -s /usr/bin/nodejs /usr/bin/node - that will symlink the node.js binary from the name Ubuntu gave it to the name it's supposed to have.
EDIT:
As mscdex pointed out in a comment (and as mentioned at the end of the bug I linked), there's a legacy package you can install that should create this symlink.
sudo apt-get install nodejs-legacy
The bug I linked above indicates that there are probably other problems with Ubuntu / Debian's default node.js package, and recommends you install your own either from the PPA mentioned there or from source.
You'll probably need to follow the advice in NPM modules won't install globally without sudo as well.

Node.js says it can't load sqlite3 module, but does anyway

I'm working with the new Node.js Tools for Visual Studio and included the sqlite3 npm module. When I call require('sqlite3') it throws the error:
Error: Cannot find module './binding\Debug\node-v11-win32-ia32\node_sqlite3.node'
Odd thing is, when I ignore the error and continue running the code, everything works fine...until the function I'm in returns; then the server crashes.
Has anyone else had this issue? I have a suspicion that it has something to do with the ./binding part, but wouldn't know where to begin in terms of finding out why.

use this:-
npm install sqlite3 --build-from-source

This is what worked for me: https://www.npmjs.com/package/sqlite3
npm install https://github.com/mapbox/node-sqlite3/tarball/master

From: https://github.com/mapbox/node-sqlite3/wiki/Building-On-Windows
Install required software:
Python 2.x: https://www.python.org/downloads/release/python-2711/
Win SDK: http://www.microsoft.com/en-us/download/details.aspx?displayLang=en&id=8279
Microsoft Visual Studio 2010+: https://www.microsoft.com/es-es/download/details.aspx?id=48217
Build:
npm install sqlite
npm install
node-gyp configure build

I got the kind of problem, my node version is v10.16.3
This globally installed sqlite3 gives error in loading by require('sqlite3')
It been solved by install a sqlite3 local to project.
$ npm install sqlite3
Note without -g option, it works for me.

It seems this is a problem with the sqlite3 npm package itself. There exists a lib\binding\Release\ folder, but not a lib\binding\Debug\ folder. I just created a copy of the Release folder, named it Debug, and all is well.

In case this above has not worked for anyone, here is what worked for me:
sudo apt install node-sqlite3
(I am using Ubuntu with Vscode as editor). It seems installing this node-sqlite3 module was the one that was recognized.

To skip searching for pre-compiled binaries, and force a build from source, use
npm install --build-from-source