node packages are loaded from wrong path - node.js

I have this issue on global packages, that if I run npm install -g <package> that packages are installed into /Users/myUsername/.nvm/versions/node/v5.0.0/node_modules which seems correct to me.
But it runs packages from:
/usr/local/lib/node_modules
Thus these packages never get updated/ if I delete a package from there and install it globally it is not available afterwards. If I copy the package after installing from the nvm to the local folder it works.
1) Are the packages supposed to be in the nvm path or in the local one?
2) How to use the correct path?

You should install all dependencies locally if you plan to use them in your node application and make sure it is listed under dependencies or devDependencies in your package.json file.
If you intend to use them only from cmd line then you can install globally so that it'll be available from any path in your terminal.
You don't need to mention from where node_modules will be loaded in your node application.

Related

npm install command - please explain

I am starting to learn React Native and I am very new to npm package manager. I read that npm can install packages localy or globaly but I am trying to understand what does that mean.
I am reading this page https://docs.npmjs.com/getting-started/installing-npm-packages-locally, can someone explain to me what does this mean please.
If you want to depend on the package from your own module using something like Node.js' require, then you want to install locally, which is npm install's default behavior. On the other hand, if you want to use it as a command line tool, something like the grunt CLI, then you want to install it globally.
Since I am very new to npm, React Native, Node (never used it), I am confused by the very first sentence in this quote. What does it mean "my own module?
If I want to use CRNA, I guess, I would have to install it globally?
If I am to install a package, say CRNA locally or globally, where do I see it installed on my MacBook Pro?
The difference between local and global install is that local install puts it into the node_modules directory of your project (this is what is referred to as "your own module") while global puts it into a system directory (the exact location depends on your OS, on OSX it should be /usr/local/lib/node_modules).
Basically:
Local install ties the installed module to your project: other projects on your computer do not get it but if your project is copied to another computer the module will be installed there too
global install ties it to your computer: you can use it on all of
your projects on your computer but if your project is copied to
another computer the installed module will not be there
And yes, CRNA should be installed globally as it is a general tool not a project's library dependence.
When you install package globally npm install -g <package name> modules drops in {prefix}/lib/node_modules.
Locally - npm install <package name> - drops package in the current working directory.
If you are going to require module in your project you have to install it locally.
If you want to run in from command line you need to install it globally.
If you need more extenden explanation take a look
Since I am very new to npm, React Native, Node (never used it), I am confused by the very first sentence in this quote. What does it mean "my own module?
If you have package.json file, then everything in the same folder is treated as "module". You add dependencies to it by doing npm install --save foo (--save option adds it under dependencies in your package.json).
If I want to use CRNA, I guess, I would have to install it globally?
Not sure what "CRNA" is. But general rule is that mostly everything (libraries...) are installed locally. Which means that they are added to your package.json and installed in same folder under node_modules.
Only case when you want to install something globally (can be added to package.json but is NOT installed in the same folder under node_modules but probably in your home directory), by doing npm install --global bar (--global installs it globally). Is when tool (not library) is project independent, as you can access it from everywhere. Something like create-react-app.
TLDR:
Local are dependencies (libraries) installed in same folder and (usually) added in your package.json as dependencie.
Global are tools installed in your user home folder and (usually) NOT added in your package.json as dependencie.
Let first start with how nodejs finds package.
Suppose you have some folder structure like-
root
-pixel
-project1
-project2
So, if your are working on project1 and required some npm package, nodejs tries to find a folder named node_modules in current directory. If fails, it goes parent(pixel folder) and tries to find node_modules and goes recursively upto root(which is global).
So, if there any package installed globally, you don't need to install it in your current working directory.
So, why don't we install all packages globally? Isn't it saves our harddisk memory?
Yes, true. But as npm packages are updating and changing its version everytime, its necessary to use specific package in your current working package to avoid collusion.
Then how global packages is useful?
Its good idea to install some cli packages to run directly from command line i.e webpack to easy our task.

one dedicated directory for node_modules

I am quite new to npm but I have a question about npm node modules. I have the node modules now installed in several directories. One for Gulp, one for nodeJS etc. I was wondering how I could have one dedicated node modules directory and let the other packages point to that directory, instead of having node modules all over the place.
What is best practise?
Cheers,
Lino
Yes, you can have global node_modules directory accessible to multiple application.
A package is available globally if it is installed with -g option. For instance if body-parser is required globally it should be installed with the following npm command:
npm install body-parser -g
Following are the paths are usage of modules:
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.

NPM on OSX, error getting global installed packages

I have nodejs installed on a MBP which runs OSX 10.9, I have installed as a package downloaded from the nodejs website. Then I have installed the MEAN stack following instructions on mean.io.
The commands are:
sudo npm install -g mean-cli
mean init yourNewApp
That works correctly
Now the real issue is when after my app is created I enter the dir using the terminal, and write gulp, and it thows me some errors that some mandatory modules are not found.
The modules are written in the package.json file that mean generated, and they are installed as global modules on ~/.npm
I browsed the folder and there are all the required packages folders, inside the folders there is a package.tgz file which has the code of the package and a package folder which holds a package.json file describing the package itself.
Now I don't understand why the packages are compressed and why if they are installed globaly can not be accessed from gulp on my project folder.
Thanks in advance.
If you install some global module then you better don't put it into the package.json of your app because when you run your app that's the first place where is going to search and if it is there your app is going to look at node_modules folder and if it is not there your app will crash.
My advice is try to install your modules inside your app, npm install your_module --save because your app is gonna be portable and with a simple npm install you will be able to install all your needed packages.
But if you still wanna install global packages you maybe wanna follow this rules:
If you’re installing something that you want to use in your program, using require('whatever'), then install it locally, at the root of your project.
If you’re installing something that you want to use in your shell, on the command line or something, install it globally, so that its binaries end up in your PATH environment variable.
If you have the time to read the link then you will see that there are exceptions and how to handle them.

Node Version Manager (NVM) npm installing modules to common folder

I've installed NVM for node.js using the instructions from this post:
http://www.backdrifter.com/2011/02/18/using-nvm-and-npm-to-manage-node-js/
When I switch between node versions and then use npm to install a module, all the modules are placed in the same 'node_modules' folder (~/node_modules/) instead of in the 'node_modules' directory specific to that version of node?
Any idea on how to remedy this?
Based on the comments from https://github.com/creationix/nvm/pull/97:
When installing packages with npm using the global switch -g the
package ends up in the proper directory (i.e.
.nvm/$VERSION/lib/node_modules), however node is unable to require it
since it somehow isn't searching on it's prefix.
So using npm install -g xxxxx will put the modules in the correct location for NVM but if you try to require one of them node can't find the module. I am still playing around with this and will update if I find a solution.
Update
Where does NPM put node_modules? (see https://docs.npmjs.com/files/folders)
Local install (default): puts stuff in ./node_modules of the current package root.
Global install (with -g): puts stuff in /usr/local or wherever node is installed.
Install it locally if you're going to require() it.
Install it globally if you're going to run it on the command line.
If you need both, then install it in both places, or use npm link.
So what I did was run npm init (see http://npmjs.org/doc/init.html) in my projects root dir which generated package.json. Now when I run npm install xxxxx it creates a node_modules dir in my project folder (which I add to my .gitignore). This works for modules that I require in my code.
For commands such as CoffeeScript I install with npm install -g coffee-script which puts it in the correct directory (.nvm/$VERSION/lib/node_modules). While I can't require these modules (npm link should solve this problem) I can run the commands - i.e. coffee.
I just installed express globally (-g) and was having problem when require("express"). Just like Jesse Vogt said I just reinstalled express but this time without the -g just like this: "sudo npm install express" and now is working perfectly!
For latest nvm window version 1.1.7.
Package was installed and placed into the respective nodejs version.
nvm use 16.8.0
npm install truffle
nvm use 16.7.0
npm install mysql

npm package.json install globally?

Is there any way to set an NPM dependency to be installed globally in the package.json file?
Whenever I run npm update all the dependencies are installed locally.
Thanks.
I believe that the -g option causes things to be installed globally.
Is your reason for installing globally in order to make new scripts available on the command line? If so, I might have a workaround for you.
Just install your packages as usual (without the -g):
npm install -S my_module_name
Including the -S flag or --save will help keep your package.json file up to date.
As usual, your project's npm install step will install locally (as you have described). However, it will also produces a local folder containing symlinks to each of the project's npm-supplied command-line executables (located inside the node_modules/.bin/ folder).
Add that folder to your system path to enable command-line access to npm modules without requiring installation via -g, or root access to a machine:
export PATH=/path/to/your/project/source/node_modules/.bin/:$PATH

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