CODEWITHSUNDEEP
javascriptnode.js
milkmanjack
milkmanjack

Reputation: 67

Unexpected NodeJS and NPM behavior

Does npm install only install packages in the directory you run it from? Because that's my current experience with it. At first, I ran npm install xml in a command prompt at C:/Users/ME. Running require("xml"); in a node instance that was run from C:/Users/ME works, and running npm ls lists the xml package...

But if I move to any other directory, neither of them do.

Is this the expected behavior (doesn't sound right), a Windows thing, or am I missing some kind of install option?

Upvotes: 1

Views: 148

Answers (4)

Mike Horstmann
Mike Horstmann

Reputation: 588

Note the way you install node is important as well!
You can install node with:

  1. chocolatey (https://chocolatey.org/packages?q=nodejs)
  2. nodeJS website (https://nodejs.org/)

*Knowing where to set your user variables is essential know how for windows developers! The reason I mention this is that the list of chocolatey, and node USER : PATH variables gets so large at one point nodejs and with it npm will just stop working. You need to work within your env. variables in one scenario where that happens. (Can typically happen with multiple versions of SQL Server installed)

If you want an excellent free, offline-available resource on node and npm I suggest devdocs (http://www.devdocs.io) and as well GentlNode's cheat sheets (https://gentlenode.com/journal/cheatsheet) *GentleNode not avail. offline FYI.

There's some key information you haven't received yet. See below:

  1. npm install xml - installs "xml" package and required modules to the local folder you are in when you run the command. Files exist for you to work on in this folder alone(and thus commands only work in this folder) and "xml" cannot be called in cmd/terminal outside of this folder(without rerunning with "-g" param) "xml" is NOT written to package.json file. When and if project is uploaded to github will upload in full if you don't add node_modules to your .gitignore file.
  2. npm install -g xml - install "xml" to your global npm folder, which is referenced to your "user environment variables" (what allows you to call specific functions, methods, and executables from within the command line) Files are NOT installed to your project folder, not recorded in "package.json" file. Will NOT upload anything to github.
  3. npm install --save xml - using "--save" allows you to "install" to this folder, but also to write the package you've included into your project's "package.json" file. Here, your aim is to distribute your software and you want as little files on github/source control as possible that npm knows how to install like jQuery, XML, body-parser, etc. etc.

You would typically use a regular "npm install XML" command for a lightweight, rapid release mini-tool to support a key feature or process improvement you just want to keep on your local machine. In addition, you could npm install "packages" to a folder, and use that as a backup "node folder" mapped to your environment variables.

You would typically use a global "npm install -g XML" command for something like middleware, express, node updates installed VIA npm, and other processes you wish to have access to in cmd/terminal from "anywhere." Once this is established for your core development packages in node, you often just use the proceeding command, read the explanation for more detail.

Lastly, you would use "npm install --save" to write into the "package.json" file the required module(s) you've installed to your project. This would be for those who have worked heavily in node and have used "npm install -g" to already globally install their most common core nodeJS. This will write to the package.json the packages and versions being leveraged in your software currently so that your end-user can download the lightweight version and use npm package management to install all of the module dependencies so the app works correctly on other people's computers. *Note, this leads to the last command "npm install" which you can run in a given folder where you've downloaded the file directly from github.

Hope that helps a bit more for the given facets of installation using npm!

Upvotes: 0

jfriend00
jfriend00

Reputation: 707218

npm installs modules either below the current directory (in a node_modules sub-directory) or if you use the -g flag when running it, it install modules in the global location which is determined via OS and configuration and then node.js will be able to find the module no matter where it is being loaded from.

So, this will install a module globally:

npm install -g xml

When using require(), if you want require to look in the current directory to load a module, then you have to do it like require("./module");, otherwise it will not look for the modules install in the current directory.

Upvotes: 2

Imran Sheikh
Imran Sheikh

Reputation: 361

You need to do npm install -g xml. This would install the packages globally.

'-g' represents global. Then when you check on other directories, you could list the same package

Upvotes: 1

Catalin MUNTEANU
Catalin MUNTEANU

Reputation: 5634

Yes, this is normal behavior.

npm install (in package directory, no arguments):

Install the dependencies in the local node_modules folder.

In global mode (ie, with -g or --global appended to the command), it installs the current package context (ie, the current working directory) as a global package.

By default, npm install will install all modules listed as dependencies. With the --production flag (or when the NODE_ENV environment variable is set to production), npm will not install modules listed in devDependencies.

NPM Install Docs

Upvotes: 2

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