NPM Guide

• NPM Guide
  • Introduction
  • Getting npm
  • npm Help
  • package.json File
  • package.json Defaults
  • Installing Local Packages
  • Uninstalling Local Packages
  • Installing Global Packages
  • Uninstalling Global Packages
  • Listing Packages
  • npm Versioning
  • Installing From package.json
  • Updating Packages
  • npm Prune
  • npm Shortcuts
  • npm Scripts
  • Author

---

Introduction

• npm is a package manager for JavaScript
• Modules - The individual files containing reusable code are called as Modules
• Package - It is a directory that contains modules with a special file package.json is called as Package package.json contains the meta data about the package.
• It is way/medium/platform to share code with other developers and reuse the code to easily manage the different versions of code by other developers
• It also keeps the uniformity between developers by regular updates
• It maintains and handles compatibility changes very well

Getting npm

• npm is shipped with NodeJs
• Download and Install NodeJs (LTS)
• Check node version by

node -v

• Check npm version by

npm -v

npm Help

• All commands of npm

npm help

• npn install is the most common command and with -h gives the more options to install the packages

npm install -h

• npm help-search <keyword> npm searches for the keyword in its documentation and provides occurances of it

npm help-search update

• Below command, download the update documentation and opens up for the use in the browser

npm install update

package.json File

• It is recommeded to add in the project folder
• Benefits:
  • Lets to manage dependencies like Working on Node project that requires Express then it is must to specify Express and its version
  • Lets to add Scripts - Helps with initial project build

  npm init
  

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

• To skip the question during npm init, we use

npm init --yes

package.json Defaults

• To set defaults like author, license, etc.

npm config set init-author-name "Abhinav"
npm set init-license "MIT"
npm init --yes

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": ""
}

• To know the default value

npm config get init-author-name
npm get init-license

• To delete the default value

npm config delete init-licese
npm config delete init-author-name
npm init --yes

Installing Local Packages

• To install packages locally on the system by npm install <package-name>
• NOTE: Be inside the project folder before installing
• Moment is a JavaScript library

npm install moment

• All packages are installed in node_modules folder in current directory
• package.json helps track the dependencies used in the project
• To save the package as dependency in package.json file, we use

npm install moment --save

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {
    "moment": "^2.27.0"
  }
}

• To install packages only for development and not for production purposes then we use

npm install lodash --save-dev

• By doing this, it creates a separate dependencie in package.json as devDependencies
• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {
    "moment": "^2.27.0"
  },
  "devDependencies": {
    "lodash": "^4.17.20"
  }
}

• From above, moment is the production dependency and lodash is development dependency

Uninstalling Local Packages

• To uninstall the local packages by npm uninstall <package-name> but this not remove the dependency from the package.json

npm uninstall moment

• To remove the dependency as well with the package

npm uninstall moment --save

• To remove dev dependency

npm uninstall lodash --save-dev

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {},
  "devDependencies": {}
}

Installing Global Packages

• Some packages like grunt and gulp need to be used from the command line and in such scenarios package is preferred to be installed globally. So that it's binaries end up in the PATH environmnet variable. But after the installation the package is not found to be node_modules that because it's not locally

npm install moment -g

Uninstalling Global Packages

npm uninstall moment -g

Listing Packages

• To view the list of all locally and globally installed packages by
• Locally

npm list

• Global

npm list --global true

• NOTE: All the global packages are stored in C:\Users\<Username>\AppData\Roaming\npm\node_modules
• To limit the depth view of the list on console

npm list --global true --depth 1
npm list --depth 1

• 1 means immediate dependencies of the package, not the full tree
• 0 means no dependencies of the package is not shown, only the package name is shown

npm Versioning

• It is important to know the working of versioning with the packages
• Semantic Versioning is a specification where a version is represented by three numbers that mean the same thing for every developer.
• For Example: "lodash": "4.16.1"
  • 4 represents the major version number
  • 16 represents the minor version number
  • 1 represents the patch version number
• Patch version number is updated when a bug is fixed or performance improvement
• Minor version number is updated when a new feature is introduced and does not break any existing functionality
• Major version number is updated when there's a break in the existing functionality
• To install a specific version of a package, @ symbol is used

npm install lodash@3.3.0 --save

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {
    "lodash": "^3.3.0"
  },
  "devDependencies": {}
}

• To install the latest patch version but specific major and minor version then

npm install lodash@4.14 --save

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {
    "lodash": "^4.14.2"
  },
  "devDependencies": {}
}

• Similarly, to install the latest minor and patch version but specific major version then

npm install lodash@4 --save

• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {
    "lodash": "^4.17.20"
  },
  "devDependencies": {}
}

Installing From package.json

• To install the packages through package.json is done using

npm install

• With ^ symbol in front of package name like "lodash": "^4.17.20" lets the npm to install the latest minor and patch version but keeping the specific major version
• With ~ symbol in front of pacakge name like "lodash": "~4.17.20" lets the npm to install the latest patch version only but keeping the specific major and minor version
• With * symbol in front of pacakge name like "lodash": "*" lets the npm to install the current latest version
• With no symbol in front of pacakge name like "lodash": "4.17.20" lets the npm to install the complete exact specific version

Updating Packages

• To update the packages

npm update <package-name>

• To update only the development dependencies

npm update --dev --save-dev

• To update all the packages including development and production dependencies

npm update

• To update all the packages globally

npm update -g

• To update the latest npm then (but run cmd with adminstrative privileges)

npm install npm@latest -g

npm Prune

• To remove the unused dependency, on seeing the extraneous packages through npm list

npm list
npm prune

npm Shortcuts

• To create package with default values

Before: npm init --yes
After: npm init -y

• To install package locally

Before: npm install lodash
After: npm i lodash

• To save the package installed in the package.json during installation

Before: npm i lodash --save
After: npm i lodash -S

• To save the package as dev dependency

Before: npm install moment --save-dev
After: npm i moment -D

• Miscellaneuous
  • --global to -g
  • npm -version to npm -v
• More Shortcuts at - NPM Shortcuts

npm Scripts

• To run the application

node app.js

• Writing script to do the task automatically, replace test in scripts with the your keyword along with the command to execute
• package.json

{
  "name": "npm-implementation",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "start": "node App.js"
  },
  "author": "Abhinav",
  "license": "ISC",
  "keywords": [],
  "description": "",
  "dependencies": {
    "lodash": "^4.17.20"
  },
  "devDependencies": {}
}

npm start

• Scripts help in fasten and easier the work for developer

---

Author

• Name - Abhinav
• GitHub - github.com/abhinavg916