npm init:

For create package.json file which will recode the dependence.

 

npm install:

You can also write like:

npm i

This is a shortcut way to write npm install.

 

For example. we want to install undersocre.js

npm install -S underscore

The way '-S' works is it will write down the dependence into the package.json we just create:

{  "name": "commonJSBroswerfiy",  "version": "0.0.0",  "description": "",  "main": "index.js",  "scripts": {    "test": "echo \"Error: no test specified\" && exit 1"  },  "author": "",  "license": "MIT",  "dependencies": {    "underscore": "^1.7.0"  }}

 

dev-dependence:

npm install -D bower

'-D' is to add dependence into devdependence which only available for the co-work.

{  "name": "commonJSBroswerfiy",  "version": "0.0.0",  "description": "",  "main": "index.js",  "scripts": {    "test": "echo \"Error: no test specified\" && exit 1"  },  "author": "",  "license": "MIT",  "dependencies": {    "underscore": "^1.7.0"  },  "devDependencies": {    "bower": "^1.3.12"  }}

 

If we have package.json, other people download our project and they just need to run:

npm i

They can install all the dependence.