02.【Node.jsModule】InstallPakagesUsingNPM

I&＃8217;m practicing my English ability lately in order to be recruited by a foreign company for my next job-hopping,if there is anything that I did&＃8217;t express precisely， please pardon me.

1. Enter the npm website and choose the module you want: https://www.npmjs.com

2. Install your package.

There are several falgs that you should know about:

(1) &＃8220;-g&＃8221;

a.Install with the &＃8220;-g&＃8221; flag, means package will be installed globally.
Install with it when you are going to use command line, such as &＃8220;grunt&＃8221;.
npm init -g [packgeName]

b.Install Without the &＃8220;-g&＃8221; flag, means package will be installed in local node module for your application.
Install without it when you are going to require the package by using &＃8220;require()&＃8221; statement in your application.
npm init [packageName]

(2) &＃8220;&＃8211;save&＃8221;

Install with the &＃8220;&＃8211;save&＃8221; flag, means it will create a &＃8220;dependencies&＃8221; section in your &＃8220;package.json&＃8221; file, and add the package you installed to it.
When someone else use your application or develop against it, they will have a complete list of dependencies that you build against.
npm init [packageName] --save

(3) &＃8220;&＃8211;save-dev&＃8221;

Install with the &＃8220;&＃8211;save-dev&＃8221; flag, means it will create a &＃8220;devDependencies&＃8221; section in your &＃8220;package.json&＃8221; file, and add the package you installed to it.
Use it when you installed something that you need to share with your other developers , but isn&＃8217;t needed on your production server. Such as things that you use for test.
npm init [packageName] --save-dev

3. Check your &＃8220;package.json&＃8221; file after installing.

The meaning of some symbol before the version of your packages:

e.g:

"devDependencies": {
"mocha": "^2.2.5" // meaning: [major version.[minor version].[patch level]
}

(1) &＃8220;^&＃8221; : update until the major version

e.g: &＃8220;mocha&＃8221;: &＃8220;^2.2.5&＃8221; means you will update mocha until >= &＃8220;2.2.5&＃8221;, but <&＃8220;3.0.0&＃8221;

(2) &＃8220;~&＃8221; : update until the minor version

e.g: &＃8220;mocha&＃8221;: &＃8220;~2.2.5&＃8221; means you will update mocha until >= &＃8220;2.2.5&＃8221;, but <&＃8220;2.3.0&＃8221;

(3) &＃8220;*&＃8221;: update to the latest version (not recomanded)

e.g: &＃8220;mocha&＃8221;: &＃8220;&＃8221; means you will update mocha to the latest version*

Related:
Create a Node.js Module and Use it Locally
Publish a Node.js Module to the NPM Registry