Nodejs NPM common instructions summary

npm What is it?

npm: Full name Node Package Manager javascript Project package management download tool , It's with NodeJS Package management and distribution tools installed together , It can be easily downloaded by front-end developers 、 install 、 Upload and manage installed packages .

Use npm The premise of

• First we need to install Node
• Official website download Nodejs https://nodejs.org/zh-cn/download/
• Download and install , It can be used after installation npm

npm Some common instructions

1. see npm Version of

npm -V

2. npm Taobao mirror ( When downloading files, Caton needs to use Taobao image )

 Set global npm Taobao mirror 
npm config set registry https://registry.npm.taobao.org
 You can also switch back to the default global image 
npm config set registry https://registry.npmjs.org

3. npm Common command abbreviations

-g：  by  --global  Abbreviation , Indicates that it is installed in the global directory 
-S：  by  --save  Abbreviation , Indicates that the installed package will be written to package.json Inside dependencies
-D：  by  --save-dev  Abbreviation , Indicates that the package to be installed will be written to packege.json Inside devDependencies
i：  by install Abbreviation , Said the installation 

4. initialization

npm init
 Initialize project   establish package.json The file of 
npm init -y
 Quick initialization project 

5. uninstall uninstal

 uninstall jquery 
npm uninstall jquery
 Abbreviation （ Alias ）
uninstall --- remove/r

6. install

 General installation 
	 install  jquery 
	npm i jquery
	 Specify version installation   Install fixed version jQuery
	npm i [email protected] -S
 Global installation 
	 Any item of the computer can be referenced to the plug-in 
	 Global installation vue
	npm i @vue/cli -g
	 The location of the global installation of plug-ins 
	npm root view -g
 Development and installation 
	 The project uses , No need to go online 
	 Development dependent installation axios
	npm i axios -D
 Product dependent installation 
	 The installed plug-ins are required in both the development and online stages 
	 The product environment depends on installation jquery
	npm i jquery -S

7. Version number

^3.6.0  Limit the version range 
 Project use jQuery Can upgrade   However, the scope of upgrade cannot be greater than or equal to 4.0.0
X.Y.Z
X The big version ,X The upgrade of is incompatible 
3.6.0->4.0.1 Use 3.6.0 And now 4.0.1 Incompatible items for 
Y Medium version ,Y The upgrade of represents an addition of new content  （ Compatible ）
Z Small version , Often repair bug error 

8. An updated version

 to update jQuery
npm Update jquery
 Alias  update --- up