We Keep Coding

Running node app without node_modules folder

My professor wants us to submit our project for our node.js app but we are not allowed to include node_modules in the submission.
When I try to run the app without the folder in there, it crashes due to missing dependencies.
Am i missing a step?

Presumably either
you're not supposed to use third-party dependencies in your solution (just the core Node.js modules), or
you're not supposed to include node_modules in your submission (which is good practice anyway), but instead just have a package.json (and possibly a lockfile) so your instructor can npm i / yarn to install the packages.

When building an app that has node_modules you aren't supposed to include this anyway.
Install any node_modules that are required for your application to run and when sibmitting just leave out the node_modules folder.
Your package file will include everything that your instructor can check over or install on their end if necessary.
I found this random example on github: https://github.com/hayanisaid/nextjs-intro-example
As you can see by looking they have there package files but no node_modules, when you clone this repo you would run npm install which would create and install the packages

package.json contains information about node modeuless.
If u deleted node modules, you just have to run npm i --save.
All the dependency will be downloaded through this.

Just use npm/yarn install if you remove the folder.

How to run my local angular project by using globally installed npm packages?

I want to do something like this, where, I want to keep all my packages globally just like node package itself. So for example in my package.json I have a package name called "Highcharts" I want to install it globally I don't want to create a local node_modules folder and use it but I want to access it from outside so next time whenever I want to create a copy of my project folder I should be able to use highcharts directly without using npm install. Is it possible?
globally installed node_modules - > Users/user/AppData/Roaming/node_modules/highcharts
app
src
node_modules (I don't want to keep it)
package.json
tsconfig.json
angular.json
How to link these globally installed node_modules with the current app or any app which we want to create?
Any help will be appreciated. Thank you so much :)

local packages are installed in the project directory
global packages are installed in a single place in your system
Usually it is a good idea to have all npm packages required for your project installed locally (project folder). This makes sure, that you can have dozens of applications which are running a different versions of each package if needed.

export NODE_PATH='yourdir'/node_modules
Hello, if am getting right, you want to keep all dependencies global.
You can just run install with -g command. Those libraries will be available in node installation folder.
From the Node docs
If the NODE_PATH environment variable is set to a colon-delimited list of absolute paths, then node will search those paths for modules if they are not found elsewhere. (Note: On Windows, NODE_PATH is delimited by semicolons instead of colons.)
Additionally, node will search in the following locations:
1: $HOME/.node_modules
2: $HOME/.node_libraries
3: $PREFIX/lib/node
Where $HOME is the user's home directory, and $PREFIX is node's configured node_prefix.
These are mostly for historic reasons. You are highly encouraged to place your dependencies locally in node_modules folders. They will be loaded faster, and more reliably.
I hope I answered, you just need to manage the paths to node_modules wherever you have kept it.

Installing gulp plugins locally vs globally

I am pretty new to Gulp and I've got a question: should I install gulp plugins (such as gulp-sass or gulp-imagemin) locally or globally? In examples around the web people mostly do it locally (with --save-dev option). As I understand, by doing so the modules are stored in the local node_modules folder, added in the local package.json as devDependencies and can be referenced to in the local gulpfile.js via require(). So, if I need to install the same modules for another project I work on, it may be accomplished by copying package.json to a new project's folder and typing in npm install in a command line tool (after getting to the project's folder). Fine.
But what if I, as a regular gulp user, don't have plans to upload and share my stuff on the npm space and not interested in maintaining devDependencies, can I in this case just install gulp plugins globally like npm install -g gulp-sass? Will they be found through a global path in my system? Is it an option on the whole, if I don't want to bother myself to copy package.json, run npm install every time I create a new project or have multiple copies of the same modules scattered around on my disk?

For plugins that you are using via gulp, what you have to do is install them locally to the project. Although you have to install gulp itself globally and locally, to run the file and then for the project to pick up the gulp based commands and functions.
The reason you should install the plugins via npm locally is so that it is specific to the project, for example if you then went to upload this project to your server or host on github then you would have to then go and have to globally install all of your packages again. If they are saved, they exist in your packages.json, this is so that when you go to run npm install to install all the packages for said project npm knows what to install.
If I can further clarify anything let me know.

A kind of "global install" for the typical case OP explained, could be to have a folder where you put your package.json with every dependencies you need for each of your projects, and run npm install from there.
And put here also your gulpfiles for each project (you could named them as you want), like gulpfile-project1.js, conf-project2.js... whatever.
Of course adjust your paths in those files accordingly.
And from this directory, run gulp using the -f flag:
gulp -f gulpfile-project1.js
So you end with this kind of scaffolding :
my_dev_directory
- project1
- dev
- main.less
- main.js
- www
- main.css
- main.js
- gulp
- node_modules
- package.json
- package-lock.json
- gulpfile-project1.js
In your gulpfiles, start to declare a const with the base path of your project to ease all path declarations, like:
const path_dev = '../project1/dev';
const path_www = '../project1/www';
This way you have only one node_modules directory installed on your disk and your projects directories contain only public files you want to upload, no dev files.
Of course one of the main drawback is that you share the same module version with all your projects, but it answered to OP's need and even if it's not recommended, not the "proper way to do", you are free to do as you want with your dev tools :)

Install node extensions without commands

I am doing an internship in a company.
I need to create a node server.
I installed node on the computer (Windows) and I should install some plugins like:
- nodejs-webpack
- colors
- uglify
Normally I need to enter a command like : npm install "theModule"
But the software can not access the internet (due to company restrictions) and support service can not authorize the software (or do not want).
Can I install modules in any other way ? (download from Google and slide archives in the correct folder for example).
If the answer is no, do you know how can i get around this security?

You need a private npm repository.
Check out this answer:
can you host a private repository for your organization to use with npm?

I found it !
Just for exemple, we will install 'nodejs-websocket' :
1) You just have to download it here.
2) Put files into your Node's directory (for me it's "C:\Program Files\nodejs\node_modules\npm\node_modules")
3) in your .js file just add this line : var ws = require("C:/Program Files/nodejs/node_modules/npm/node_modules/nodejs-websocket/")
Done ! Thanks for all :D

I added this as a comment on your own answer, but I figured I should add a real answer with a better explanation.
Normally when you run npm install package-name npm installs the package to a node_modules directory in the directory you are in at that moment. So if your app was located at C:\code\my-app then you would cd into that directory and run npm install package-name. This would create a node_modules directory at C:\code\my-app\node_modules if it didn't already exist. Then it would install package-name into that directory at C:\code\my-app\node_modules\package-name.
As long as the module is in the node_modules directory for your app, you can require the module in your code without entering a big long file path.
var ws = require('nodejs-websocket');
The place you manually installed your module is the global node_modules directory. It's where npm would install a module if you did npm install -g package-name. The global node_modules directory is added to your system path when you install npm. In other words, any modules you install in there would be accessible from the command line like any other command. For example:
npm install -g bower
That would install the "bower" package to the global npm module directory. Bower would then be accessible as a command line tool for you to use. For example:
bower install angularjs
The global directory is more for tools like that and not really for modules that you intend to use in your code. Technically you can require a module from anywhere by including the full path in the require call like you did, but the standard practice would be to place it in the node_modules directory in the root of your application, and then require it with just its name and not a full path.
Edit: Here's another tip that you might like to take advantage of as well.
When you normally install a module with npm install package-name, your application usually has a package.json file at the root of it. If it does, you can do npm install package-name --save and npm will add the package-name module to a list in your app's package.json file. Once a module is listed in your app's package.json file it's called a "dependency" of your app because it basically says your app depends on package-name.
Normally, when you have dependencies listed in package.json, you can completely delete your app's node_modules directory and then simply run npm install from within your app's root directory and npm will automatically install all dependencies it finds listed in your app's package.json file. Since your corporate firewall won't allow this automatic downloading of modules, you won't get that benefit. However it is still good practice to follow the same conventions.
A trick you can do to create your package.json file is to manually install your dependencies into your app's node_modules directory. Once you have the modules your app needs, you can instruct npm to create a package.json file for your app by simply running npm init. It will walk you through a few little prompts to fill out your package.json file with details about your app. It will then peek inside your node_modules directory to see if you've already installed any modules before having a package.json file. If it finds any, it will automatically add them to the dependencies field in the package.json file it creates :D
With a proper package.json in place you'll always have a nice tidy list of what dependencies your application needs, even if your node_modules directory gets deleted. Normally people add their app's node_modules directory to their .gitignore file, only checking in the package.json file. This way they don't store their dependencies in source control but they can still be easily installed on new machines that clone it by simply running npm install from inside the app's directory. In your case though you may want to just add node_modules to your source control since you can't let npm install dependencies automatically.

Why do we need to install gulp globally and locally?

2 manuals about gulp say that I need to install gulp first globally (with -g flag) and then one more time locally. Why do I need this?

When installing a tool globally it's to be used by a user as a command line utility anywhere, including outside of node projects. Global installs for a node project are bad because they make deployment more difficult.
npm 5.2+
The npx utility bundled with npm 5.2 solves this problem. With it you can invoke locally installed utilities like globally installed utilities (but you must begin the command with npx). For example, if you want to invoke a locally installed eslint, you can do:
npx eslint .
npm < 5.2
When used in a script field of your package.json, npm searches node_modules for the tool as well as globally installed modules, so the local install is sufficient.
So, if you are happy with (in your package.json):
"devDependencies": {
"gulp": "3.5.2"
}
"scripts": {
"test": "gulp test"
}
etc. and running with npm run test then you shouldn't need the global install at all.
Both methods are useful for getting people set up with your project since sudo isn't needed. It also means that gulp will be updated when the version is bumped in the package.json, so everyone will be using the same version of gulp when developing with your project.
Addendum:
It appears that gulp has some unusual behaviour when used globally. When used as a global install, gulp looks for a locally installed gulp to pass control to. Therefore a gulp global install requires a gulp local install to work. The answer above still stands though. Local installs are always preferable to global installs.

TLDR; Here's why:
The reason this works is because gulp tries to run your gulpfile.js using your locally installed version of gulp, see here. Hence the reason for a global and local install of gulp.
Essentially, when you install gulp locally the script isn't in your PATH and so you can't just type gulp and expect the shell to find the command. By installing it globally the gulp script gets into your PATH because the global node/bin/ directory is most likely on your path.
To respect your local dependencies though, gulp will use your locally installed version of itself to run the gulpfile.js.

You can link the globally installed gulp locally with
npm link gulp

The question "Why do we need to install gulp globally and locally?" can be broken down into the following two questions:
Why do I need to install gulp locally if I've already installed it globally?
Why do I need to install gulp globally if I've already installed it locally?
Several others have provided excellent answers to theses questions in isolation, but I thought it would be beneficial to consolidate the information in a unified answer.
Why do I need to install gulp locally if I've already installed it globally?
The rationale for installing gulp locally is comprised of several reasons:
Including the dependencies of your project locally ensures the version of gulp (or other dependencies) used is the originally intended version.
Node doesn't consider global modules by default when using require() (which you need to include gulp within your script). Ultimately, this is because the path to the global modules isn't added to NODE_PATH by default.
According to the Node development team, local modules load faster. I can't say why this is, but this would seem to be more relevant to node's use in production (i.e. run-time dependencies) than in development (i.e. dev dependencies). I suppose this is a legitimate reason as some may care about whatever minor speed advantage is gained loading local vs. global modules, but feel free to raise your eyebrow at this reason.
Why do I need to install gulp globally if I've already installed it locally?
The rationale for installing gulp globally is really just the convenience of having the gulp executable automatically found within your system path.
To avoid installing locally you can use npm link [package], but the link command as well as the install --global command doesn't seem to support the --save-dev option which means there doesn't appear to be an easy way to install gulp globally and then easily add whatever version that is to your local package.json file.
Ultimately, I believe it makes more sense to have the option of using global modules to avoid having to duplicate the installation of common tools across all your projects, especially in the case of development tools such as grunt, gulp, jshint, etc. Unfortunately it seems you end up fighting the tools a bit when you go against the grain.

Technically you don't need to install it globally if the node_modules folder in your local installation is in your PATH. Generally this isn't a good idea.
Alternatively if npm test references gulp then you can just type npm test and it'll run the local gulp.
I've never installed gulp globally -- I think it's bad form.

I'm not sure if our problem was directly related with installing gulp only locally. But we had to install a bunch of dependencies ourself. This lead to a "huge" package.json and we are not sure if it is really a great idea to install gulp only locally. We had to do so because of our build environment. But I wouldn't recommend installing gulp not globally if it isn't absolutely necessary. We faced similar problems as described in the following blog-post
None of these problems arise for any of our developers on their local machines because they all installed gulp globally. On the build system we had the described problems. If someone is interested I could dive deeper into this issue. But right now I just wanted to mention that it isn't an easy path to install gulp only locally.

Just because I haven't seen it here, if you are on MacOS or Linux, I suggest you add this to your PATH (in your bashrc etc):
node_modules/.bin
With this relative path entry, if you are sitting in the root folder of any node project, you can run any command line tool (eslint, gulp, etc. etc.) without worrying about "global installs" or npm run etc.
Once I did this, I've never installed a module globally.